lost

I am 100% new to this… sorry for seeming dumb…

I understand possible reasons why some info is not clear or easy to find… But now that I have kodi installed, I have no clue what I need to do next to just watch what I got this to watch. The how to install for iMac was great. No probs. But then nothing says what I need… 3rd party repos (btw the first post collection for that forum is full of 404 pages, one after another)… pvr… I have no idea what a per is!

I am not an idiot, I just walked away from mainstream tv several years ago so I never bothered having a tivo or any of that. I don’t even OWN a tv. I have been watching free stuff online – free documentary sites and lots of youtube. I just want kodi so i can watch a few things I miss or couldn’t see in theatres etc.

I understand why some content sites or whatever might not be clearly labeled. But I need to know how to figure out what I need to go get. To watch a show that still airs, but I want to see about 2 years of back episodes, what do I need to add? a 3rd party repo? If so… how do i figure out what one will do what I need? How do i avoid having to go through dozens of 404 errors to find one?

So I just need to know the basic info so I can figure out the rest myself. The how to section assumes we all know this, and well, we all don’t. I just wanto to watch a couple of things now and then using the iMac.

Helpful responses much appreciated..