MicroSD shows up as Boot and Recovery Drives

I’m not sure if this is normal but whenever I plug the default MicroSD to a computer it shows up as Recovery and Boot drives. Also whenever I try to download something to the drive it tells me there is not enough space.

This is by design. And the large partition doesn't show because Windows doesn't recognize that kind of filesystem by default. There is EXT filesystems drivers that you can install in windows to read/write to that partition.

This is an OS, not a program. You have to install it like the Raspberry Pi OS. https://octoprint.org/download/#octopi