Question cause I have an IQ smaller than a grain of rice.

So I got Skyrim legendary this weekend. Obviously it came with a disc. Now as stated, I have very low IQ so I am in need of help.

I did read previous post on this forum, just need to be sure I understood it.

I put the disk in the drive and Yada Yada Yada ... long story short, something pops up on screen, I follow the instructions and.... wait for over an hour for the damm thing to load and install. I belive it downloaded the client from steam and not from the disc as i was expecting, because it made me register a steam account first before installing the game.So now I'm getting used to playing (testing the game to be more familiar..just done doing maybe 4 or 5 main q's with 2 different toons. I also am now starting to "experiment with mods using nexus, workshop, SKSE and by tonight maybe installing LOOT aside from the many mods I have decided I like to be in the game.

Hey wake up!!!! Lol ... long story no?

Anyway, here's the question:
I am almost 110% sure I'm gonna mess up the game soon due to all the "experiments" with mods and stuff so,

When that happens, I plan to reinstall every single thing related to the game and reinstall from scratch. How do I do that w/o downloading the client from steam. I assume the client is on the disk that came in the box ya?

Do I need to also Uninstal steam to do this?

Thanks
Tuna

Format PC
Asus Sabertooth mb
3770k i7
32 gb ram
2x Asus 7870 vidcards (4gb total)
2x 256gb crucial M4 SDD drives
Win8 pro (don't hate!)