Hello, I am from Russia and I have a question if I make a game on your engine and want to sell it, for example, in steam. Do I have to give part of the money from sales or do I need to buy an engine before creating a game? Thank you in advance.
You need to pay Epic 5% of gross revenue after the first $3,000 per product per calendar quarter.
Here is a link with the info you need:
How to transfer my money to Epic?
I did not find it here Frequently Asked Questions - Unreal Engine
There is a form you need to fill. You report your revenue and royalties to Epic on a quarterly basis. Also you need to contact or inform them before you release your game or project to the public. you can write them licensing@unrealengine.com