Sorry : ( Could someone help me understand...

Hi, my name is chark and I have spent a couple of hours on this site trying to figure out what exactly to do. My friend and I are trying to join a campaign but neither of us are pros. Anyways...She is a complete newbie and I have only done in person campaigns, hopefully that can change :). Thanks for even clicking on this. oh! and I'm a huge fan of all this stuff.

OH yeah i forgot...the thing i don't really understand is how to have a campaign over this site, or is that even a thing at all? Or do i need to buy the books? 

The main way that Dndbeyond helps with campaigns is letting you make characters and store them in a campaign made by a DM as well as giving access to the various books, at least thats what I think. You don't really NEED the books but they provide the extra content in case you want to use it, but you also get access to the books of the DM of a campaign you are in if they enable content sharing. So a good place to start is finding someone to be your DM, there are plenty of LFG threads on here and reddit, theres also the discord server which has a LFG section. That DM'll give you a link to the campaign and can probably help you with making a character. 

im starting a new campaign and would love for you to join ill helpwork through the confusion