IG is just the posting pix/vid feature of FB that's optimized for your phone. it's got tools to edit your pix and stuff built in. you can look at and search for pix and content on a computer but can't post from one; just on the phone. post content or search, follow, comment, like, etc. ect. i'm not on much but it's pretty easy to figure out that a dum-dum like me can do it.
Edit: also FYI - u will find out quick that everyone on IG is either a model or rich multi-millionaire if u don't find your lane/niche.