Garry's Mod a.k.a GMod, is a sandbox game that is used in many ways, like animations, Roleplaying, Combat, HORROR, and more! And with workshop add-ons you can play game-modes like: Prop Hunt, Hide and Seek, Guess Who, Murder, Deathrun, Zombie Survival, and others. But I will talk about those later on. But first we need to get you through your first obstacle: The menus!

Play
Takes you to a map selection menu, which we will cover in a minute.
Scroll all the way down this section if you want to jump right in!
Find Multiplayer Game

• Wanna just play online with friends and have fun?
  
• Go ahead! Just have to get an invite from a friend if it is private.

Addons
Look at what the community has created!
Lots of stuff here, but some addons require other games to be on your computer.
ERRORS ARE BAD!

Demos
This is where you can watch your created demos, which are like videos but they require addons for you to view some objects,

Options
Fine tune your game to your liking

Quit
Closes the game!




Stop scrolling here
VVVVVVVVVVV

Hit Play and we shall get started!

Now, you won't have many maps to choose from, but there are a lot of community made maps for you to explore!
For now let's just stick to the basics
For this guide what you want to do is click GM_Construct, now the map has been selected.
look to the right of your screen, you will see some buttons and boxes,
For now let's stick to single player.
Don't bother touching the single-player button, that is for selecting the maximum amount of players for a multiplayer game!
I will cover multiplayer later.
There is a Text-box, but that is advanced stuff. Put something in it to activate persistence mode!
This adds something that I will cover in a minute
There is a max ammo text-box, by default it is set to 9999, which is the highest amount of ammo obtainable. Change it if you want to set a specific amount of ammo for every player, which is primarily used for Player Vs. Player related servers.
You should see three little boxes,
Give weapons on spawn
This will give you the following:
These weapons are from the Half-Life Series
Crowbar
Gravity Gun
Physgun(Always given unless certain commands are entered, but that is advanced stuff, and it will mess up your game if you don't know what to do)
Pistol
357. Magnum
SMG
Pulse Rifle/ AR2
Shotgun
Crossbow
Grenade
Rocket Launcher
Camera(Always given, much like the Physgun)
Toolgun(Always given, like the camera and Physgun)
Players have god mode
-You are invincible, unless a kill command is used.
Enable H.E.V Suit
This gives all players limited use of the Flashlight, and Sprint. Shows a energy meter when one is used.Refills energy when neither is used)
Now that this sidebar is explained, hit Start Game!

--As a thanks for the 500+ visitors, I'm going to add more sections!--

Now, let's talk gamemodes. They change how the game will be played, and I will talk about some of the known gamemodes

-Sandbox-
This is the core gamemode, you do whatever you want in this.

-Trouble in terrorist town-
This is a multiplayer gamemode, you can't play this in singleplayer.
It's a combat focused gamemode, there are 3 teams: Innocent, Traitor and Detective
Innocent- They have to avoid death from the traitor.
Detective- This player will have to try to kill the Traitor
Traitor- Their job is to kill everyone, without being killed.

Guess Who-
This is a kinda hard to explain
You need a lot of nextbot npcs for this gamemode to work, This is also a multiplayer mode, play with friends!
There's the Hiders and Seekers
Hiders can morph into a npc and try to blend in
Seekers- They need to try and kill the hiding players

Murder-
Several players are needed
You are in a map, with other players
You got the innocent, detective, and murderer.
Innocent- They need to avoid being killed by the murderer, and collect certain items
Detective- They have to kill the murderer, and not die in the process
Murderer- KILL THEM ALL

Prop Hunt- Several players need to hide as objects in the map, amd not get found by the seekers
Hiders- Morph into objects on the map and try not to get found
Seekers- Kill the hiding players.
The seekers lose health for every non-player prop they attack


Zombie survival
It's easy to figure out
Survive waves of zombies

There are other gamemodes, but I don't know what they are currently.

This section is a bit different- I cut my knee open on the fourth of july, and I am tired. I will try to give better descriptions.
Stay Safe!
-NekoOccult

Now it's time for basic gameplay
WASD to move
q to open the most useful menu in the game: the spawnmenu
1 2 3 4 5 6 to switch weapons
e to pick up objects/ open doors/ interact with objects
r to reload
ctrl to crouch
f for flashlight
t to spray(Multiplayer only)
y u i to chat
space to jump
alt to move slowly
c to open the context menu, you can change your character here, applies after death(unless you have a addon that allows you to apply it anytime)
left mouse to shoot
right mouse to use alt-fire, drop objects, secondary option for toolgun, Aim(Crossbow) and ADS(Add-on weapons)
mouse to look
mouse wheel to scroll weapons
F12 to take a screenshot
F1 to keep the spawn-menu open instead of holding q
Shift to sprint
Z to undo the last spawned tool/object/NPC/entity etc.
V to no-clip
` to open the console commands menu
Esc to bring up the pause menu(Doesn't pause in multiplayer)
R - Unfreeze objects with phys-gun(You have to aim the physgun at the frozen object)
Double Tap R- Unfreezes all Objects
There are more commands that some add-ons use.

Now for my favorite part! WEAPONS
I'm just going to cover the preinstalled weapons, if I was to list EVERY weapon mod I have installed, I would be writing this part forever.
Half-Life 2
I'm only going to cover the weapons that you don't spawn with.
S.L.A.M
A mine that has two functions, a throwable mine that can be detonated with right-click, and a motion sensor mine, which is only usable on walls, they have a laser, if anything crosses that laser, it will detonate.
Bug Bait
This one's hard to explain, it only works for Antlions and Antlion Guards
Left click to trow, it will get any nearby antlions to go to it, right click just... Squeezes it?
Stunstick
This is a melee weapon, it is more powerful than the crowbar, but it swings slower.
-other-
These contain the Medkit, and the Manhack gun.(I have too many weapon mods, I can't remember what came default with the game)
Medkit
This heals 20 health per left click, but it has to cooldown and charge for more use. Right click heals NPC's, and other players.
Manhack Gun(Admin)
Left-Click fires a manhack
Rightclick fires a rollermine