Right, read the Electronics section on the v1 site on how to wire up the steppers.
I missed that you wrote “Cocoon Create Touch”, I thought you had a Cocoon Create (same as my Duplicator i3). Your board does actually have a ATmega2560 (like my MKS Gen L), so storage should not be an issue. However it seems it’s not supported in Marlin 2.0 yet (especially the touch screen). There is a Marlin 1.1.8 fork for it, but I don’t know whether that supports all of the features needed for the lowrider.
If you want to use electronics that’s different from the ones that Ryan provides firmware for, you have to compile it yourself. That requires setting up PlatformIO or Arduino and changing the configuration to match your hardware. If that sounds daunting, I would suggest to ditch your board and display and pick one of the supported boards (e.g. a mini rambo) and get a reprapdiscount graphic smart controller.