Likely the same way as TuneCore and the rest of them: start a free account, upload your mastered tracks to build your (album/single/etc), upload the artwork, choose which stores and streaming services you want to be distributed in, hit “publish”. Done.
You get charged (or not), and then wait for the royalties to start streaming in. TuneCore pays me monthly, but most of the payees are 30-60 days behind their reporting (Apple Music, Amazon) to 6-7 months behind reporting (Napster).
How much you get depends on the store/streaming service and the distributor you choose to go with. TuneCore lets you keep 100% of what you make, but you pay annually to keep your music distributed. Apple iTunes sales pays you 70% of everything you sell; Apple Music pays you tenths of a cent per stream (all of the streaming services pay something different).
If it’s a hobby, might be best to go with the free services. If you have a fan following or more aggressive business practices, TuneCore and similar are expensive but offer fantastic reporting (you can see what part of the world your fan base is located, making it easier to plan tours to maximize exposure, etc).