Season Two for macOS only has Episodes 1-3.
The install is pretty simple, on a 32-Bit MacOS version, run the dmg file, follow the instructions, and you're set.
64-Bit (macOS 10.15 or higher)
Running the game on 64-Bit MacOS versions is a bit more difficult, but still possible.
If you have an Intel-Based Mac, you can run Bootcamp to run the Windows versions. If you have an Apple Silicon Mac, you can either:
Run the Switch version via Ryujinx. You can get both Seasons from the download links on the Switch page.
Unfortunately getting Ryujinx set up properly is a bit tricky and it's risky to post the Switch firmware/keys here. But with a bit of research they're easy to find.
Use UTM to run the Windows versions. You can download UTM here and get the downloads from the Windows page.
Or read the guide below
Apple Silicon Macs (M1, M2, M3 etc.)
Running the game on Apple Silicon Macs is possible, but you need a software called Sideloadly and similarly to the iOS version you need to sideload it.
Start by getting Sideloadly here, then scroll and press macOS.
Download then open it and install it
After you've done that, you have to start the sideloadly app.
After that, fill in the Apple ID space, if you have 2FA it will send a notification with the code.