League of Legends (LoL) Question: I'm new
So basically, I'm starting on Riven and I want to get good at her, but I'm having a hard time understanding how the items work. I looked up a build for her, and the items all cost so much gold that if I get the long sword and then wait to get enough gold for the Black Cleaver I end up lacking dmg early on which just screws me later. I realize that there's obviously stuff I'm supposed to get in between those two items but I don't know what to get and when to get it.
Sorry for the dumb question but everywhere I look for an answer it's basically in a whole other language to me since I don't know anything about MOBAs.