I just downloaded the sims 4 yesterday and tried installing mods.
I just downloaded 2 mods which are new hair styles.

They are a package file so i placed them in the mods folder.
When i entered the game to play a window popped up saying "maxis does not pre-screen or support mods".

Under that there is a list of "non script mods", and under it it shows the 2 mods i installed. And under the "non scriped mods" list there is an other list of "script mods" and it has nothing in it.

I dont know what non scriped mods or script mods mean... So i ignored it and when i was going into CAS the mods werent there. So i did a research and tried enabling script mods in game options/other. I tried deleting the mods folder and let it regenerate. But nothing worked.

Please help!

That sounds like it's in working order. First of all: Things like clothing, hair, accessories, furniture, etc. needs the mesh in order to show up properly. So when you download these items, it is very important to make sure there is a link to the mesh, or the mesh is included in the download. Usually the description of the custom content will tell you if it has the mesh or not, and where to get it if not. This is probably why the hair you downloaded and installed into the mods folder are not showing up in CAS.

Secondly: The non-scripted and scripted lists don't really make a difference for you, since you are a casual user. (Correct me on this next part if I am wrong!) Non-scripted mods are things like hair, and furniture, make-up, y'know; the pretty stuff. Whereas scripted mods are more of changing the game-play, and coding.

The mod includes a mesh i just dont see the option to slect the hair it is not there... And in the download description it say that it is not a recolor its a new hair option.
Is there a solution to my problem?

Do you mean the game is a pirated version? You said you just downloaded it.
If the game is Pirated then please don't bother asking as no one will help you.

If you purchase the game through Origin, you have to download it. Not necessarily a pirate issue.

I have lots of cc on my sims4, downloaded from the free content sites. In CAS, much of it shows in the thumbnail as an alien suit, no pictures of the actual cc. When I click on it, it shows up on the sim in CAS fine, but it's hard to pick an outfit when you can't see it until you put it on. Any suggestions?

Here is a suggestion.... Read the following thread and then search this site. Your question has been answered a million times. Happy Reading
http://www.modthesims.info/showthread.php?t=551495

I just searched this site for Broken CAS and found heaps of answers to your question....