Hi!

I hope there is a generous person out there that doesn't mind explaining a few simple things to an amateur

I'm currently converting an old 10-speed bike to a fixed gear and am kindof learning as I go. I've never worked on bikes before but I'm slowly getting the gist of it, but I apologize if my questions seem clueless!

I would like to get a new, cheap crankset with only one chainring and I've been reading up on it online (there's a bike co-op near me where I could definitely find one). I am having trouble understanding what BB length I should look for and how it relates to the chainring, as well as, how to choose what length crank arms I want? If anyones willing to explain this to me, I'd really appreciate it!

Thank you.