When you first encounter the goat standing near your grandma try to use the machete on it.
Continue on the road until you find the small house,enter the house and look at the family photo on the wall.
Click on the little kid in the middle.
After you unlock the door you will see a small looking church near the shore of the island,enter it and look at the water in the middle.
Click on the water couple of times until you see your reflection.
When you find the casket and open it look to the right of the open casket and click on the barely visible symbol.

This achievement will be missed if you give your sister the flute first.
First go inside the small church and grab the belt from the stool and after you grabbed it do the puzzle on the other side of the room and grab the flute.
After that go to your brother that is standing in the start of the level and put the belt on him and make him drop his frog, back off him and zoom on him again and give him the flute.
Near your sister there is a memory puzzle that you have to complete to advance the story and grab the frog.
After you finished with the puzzle and grabbed the frog click on the water couple times until the figure with the deer mask will appear next to your reflection.
Give your sister the frog flute and complete the puzzle.
After you completed the puzzle and grabbed the frog back out from her and zoom back and then zoom in on her eye and click it couple of times until the symbol appears.

Go to the small church where your grandma is sitting and click on the log to the right.
Pick up the axe and hit the log around 10 times with the axe until the third symbol appears.
Now that you have the axe you can use it to the the tree with the X mark on it and continue to your brother sitting near a small tree with another X mark on it.
Zoom in on the tree and use the axe on it, after you got done and got the sweet for the brother back out and zoom on the tree 2 times until a butterfly will appear top of the log of the tree, click on the butterfly.

This achievement is very missable, you need the orange flowers for this achievement so don't use them before getting it.
First finish the food puzzle with your brother and he will swarmed with gnats, clear the gnats and your brother will be turned into a huge lice and he will spit a flower seed.
Grab the flower seed and go to the small house that your sister and uncle are hanging out and put the seed inside the flower incubator.
Grab the flower and head to the small church, when you enter the small church put the flower on the left window and back out the church.
After that come back in and you will see Harvey near the flowers, click on him.

Go to the small church and click on the right window couple of times until a corrupted soul appears.
After you released your brother and he killed the bunny, go back to the bunny and click on him and a familiar hand will rise from the ground.

When you done with all the puzzles for the hearts your brother collected and opened the sealed door with the diamond you will enter a room where your dad is sitting.
on the right side of the room there is a book, open it and reach to the cover of the book and press the small square on the top left until the symbol appears.

When you start you will notice a cow, approach the cow and press his head 3 times.
You have to find the boar twice, first time is in the middle of the woods behind the trees,if you don't find him back in and out of this location until he shows up.After that he will show up again in the road to the church.
Very missable! you need this cheese for your uncle burger but don't put it on the bread, first take the knife from the small house and go to your father next to your uncle and remove his bandages with the knife.
After that back out and zoom on him again and give him the cheese. Very missable!!! you have to put the ingredients exactly like the recepie next to your grandma

1. Lettuce
   
2. Burger
   
3. Cheese
   
4. Bacon
   
5. Ketchup
   
6. Cucumber
   
   
   The Fifth Symbol
   After you Uncle ate the burger he will go to the restroom,give him the bandage and zoom in on the holeDon't hurry, continue slowly until you see a barely visible symbol then click on it

go to the plague doctor, next to him there is a small pile of leaves.
Click on the pile of leaves and start moving the leaves with your mouse until you see the symbol, then click on the symbol.
Take the bottle of blood from the plague doctor and give it to your grandma to smell, when she smells the blood she will get a nosebleed.
Right next to your grandma you will see your unlce, click on him and then click on his right nipple.
After that click on his nipple couple of times.

Do the puzzle with you sister skating on the ice,after you done with the puzzle the ice will start to break.

after it breaks click on the hidden fish under the ice.
Go to the church and look in the middle where the water is suppose to be, but instead you will find a hammer.

Grab the hammer and use it to break the bottom of the circle and a hand will pop out.
After you done with the snowman puzzle and got the 3 diamonds charge up the the snow globe and use it to destroy the church.

After you destroyed it click on the rubble right beside it and you will see the symbol just click on it.

In this achievement you have to find the butterfly 4 times.

The first time.
The second time.
The third time.
The fourth time.
For this one you have to find the corrupted soul 6 times.

First time.
Second time.
Third time.
Fourth time.
Fifth time.
Sixth time.
For this one you take the eyes of the goat after he was killed by the huge locust and give them to your sister in the small house.
Press the left eye and press the gray circle couple of times until the symbol shows up.

This achievement is very missable if you're not fast enough, For this achievement you have to finish the puzzle with the 3 fires
After you finished the puzzle go to the shore where the destroyed church is and quickly click on the flying owl on top.
For this one you have to open the box near the shore where the huge owl statue is floating there.
after you opened it and collected your mother bones you have to click on the box couple more times and you will get a crows egg, go to the camp fire and throw the egg inside.
The Ninth Symbol clues are on the drawing on the wall : 1 dot (eye) in the Lion, 2 dots (eyes) in the Bull, 3 dots (bones) in the fish, 4 dots on the vase, and a V on top of the scales.(credit to lingoyen20 thanks for the help in the comments)

To find this symbol you have to make the arrow for your uncle with the feather from the owl and the bone from the puzzle with your dad
After you made the arrow make your uncle shoot your brother in the arm, take the arrow out and start to tear his sleeve until his tattoo shows up, its the tenth symbol
When you are collecting the masks in the catacomb you will reach the place where you need to collect the black cube, don't leave inspect the area where you took the black cube and use the brush on the X marks on each side to open a new puzzle
You need to put every symbol in the order we found them every day all the 10 symbols for the achievements like in the picture above, after you done take the owl mask
LAST MISSABLE ACHIEVEMENT go out and continue the story but don't forget about the owl mask we picked up
right in the end of the game put the owl mask on the corrupted soul and thats it!