Yep, you just pay the fee $100USD and that buys you a token that you can use to post a item. It’s not much more complex than Apple’s process as far a signups go…
https://partner.steamgames.com/steamdirect
Once you have a “partner account” create your game page and community pages… These are pretty simple. You upload images to the Steamworks site an use a Markdown-like sirte to build descriptions. Here’s SKIPCHASER’s page (*cough* *cough*) if you want to try out purchasing and reviewing
https://store.steampowered.com/app/508410/SKIPCHASER/
Once you are ready to test your game, the easiest thing is to start with a WIN32 Build and upload it with the SteamPipe GUI tool and flag it as a BETA. Then you can give away keys that just unlock BETA builds while you work the kinks out. You could do all this via a CLI, but this tool is dead simple.
https://partner.steamgames.com/doc/sdk/uploading#steampipe_gui_tool
Once you are ready to rock, set your price, flag it as ready to release and after a minor review your game is for sale.
All in all, once you have the upload process figured out it super easy to make new beta builds, test those out and then switch branches to make the beta the public branch.
There’s a bunch of other stuff you *can* do with DRM, cross-platform with one content directory, etc. But I’d reco doing a basic Win32 build first. We only sell about 15% via the Mac Steam store.
Hope that helps!