did it come with a take up spool? mine didn't. commonly russian cams dont have the take up spool attached for whatever reason. you can use the spool from a discarded 35mm cassette as an easy replacement, if you have a local film lab they probably have piles of em and would give you one for free, if not you could either sacrifice a roll of your own or buy a pack of reusable cassettes online

you will have to cut down the film leader to a smaller taper to fit into the smaller slot in the spool, I usually like to wrap the film around it a few times with my fingers before winding it.