Unreal Engine to Steamworks

I am a VR developer that is ready to release my game on Steam. I created the Steamworks page and completed everything in the “Store Presence” and “Game Build” checklist except the “build configured” checkbox. I have a game packaged and ready to go but I’m not sure how to upload the .zip file itself to Steam. I’ve published games on Viveport ans elsewhere before. Any help is appreciated.