Find more information about the Bogatyr squad

This step has nothing to do — it's a milestone marker the game ticks once you've collected enough items from Ryabina (and the next outposts: Carousel on Interchange, Gnezdo on Interchange). Don't try to hand anything in or talk to Prapor; just keep looting outposts and the checkmark fires on its own. Treat this as a free completion you'll get while doing the next two real steps. The Bogatyr arc is a slow-burn investigation — you're piecing together what happened to a BEAR special-forces squad that vanished in Tarkov, and Voevoda (the squad leader) won't talk to you over the radio until you've shown enough proof you've been to their camps.