Hi, you don’t have to purchase any additional tools to upload your project to Steam all you need. Is a Steamworks account and create a Project there (this will cost 100$ for a steam direct fee if I’m not wrong) so you get your SteamAppID. You need to insert your SteamAppID in the DefaultGame.ini
[OnlineSubsystem]
DefaultPlatformService=Steam
[OnlineSubsystemSteam]
bEnabled=true
SteamDevAppId=480
SteamAppId=480
(480 should be the default one which every dev can use for testing replace it with your id)
To upload you need the Steamworks SDK and I think best is when you follow the tutorial to how to upload a depo.
Tutorial Video
It’s confusing doing it the first couple of times.