So how do I do... anything?

The uConsole runs Debian by default. You might want to look up tutorials for new users on how to use Debian or play games on a Raspberry Pi 4.

Which uConsole did you get? If you’re on the uConsole CM4, Rex complied a version of Debian that’s newer and includes bug fixes for the screen and battery. Bookworm 6.6.y for the uConsole and DevTerm

If you are interested in playing games, Rex also complied a build of Retropie for the uConsole CM4. The advantage it has over Retroarch in a desktop environment is it draws directly to the frame buffer, significantly improving performance. RetroPie for uConsole and DevTerm CM4

ClockworkPi’s more of a hardware company than a software company, so I view the SD card bundled with the uConsole as more of a proof-of-concept than something you’d want to actually use.