I didn't know anything when we got our last Syrian about 4 years ago. Some I learned on here and some trial and error with what seemed to meet hamster approval
Initally I bought bags of white paper strips for nesting, but toilet paper works out cheaper and it's a bit softer and it was recommended to me. I tried all kinds of substrate and was allergic to some so I like the paper based ones. You don't need to worry about the substrate not absorbing odours etc - Syrians are quite easily toilet trained and will just use a potty - although they do sometimes pee in the wheel.