Primitive Plus is going to be released as a free DLC in about a week. I would hold off until then to see how that is going to work.
It is a great mod and I can't imagine playing ARK without it now. The release date is July 28th.

Its not my server so I don't get a choice. The server owner will set it to P+ as soon as it is released so I need to know how to play it

Well... you play pp just like normal ark except it is more in-depth. You need to do a lot more as far as crafting materials to get other materials and you have a lot more choices for building materials.
You have a lot more seeds to plant in your crop plots and you need to save your seeds to make organic oil.

Besides thatch, wood, and stone, you also have brick, cement and adobe. There is sooooo much involved with primitive plus. One very confusing thing is how the meat works but I don't think it is working correctly yet. You have bacon, fat and ribs that are not in the vanilla ark. Fresh meat and spoiled fresh meat are a thing, too.

As far as end game and what I wish I had known at the beginning... I wish I had waited until the official release to play. We have had to go through a lot of changes and a lot of frustration while the bugs have been being worked out. You can look at the different threads here and see that for yourself. :)

A lot could still change before the release next week.

I would highly suggest being part of a tribe and each person concentrating on 1 or 2 things because it takes so much to do things. There are a lot of new plants and recipes, there are many new building materials. There aren't many videos on it that I've found to give a good explanation, but there are plenty of discussions here about things, so I would suggest reading up on it until it goes live.