Mike, first thing youll need is to pick what radio you want to use
many many folks like the Alinco DR135 as it has a dsub9 connection on the back
that lets you plug a RIM-Alinco right in the back
and run the USB cable to a Raspberry Pi3 (dont use a Pi4 yet,software isnt quite ready)
you can also use a 16 pin Motorola Maxtrac/Radius radio with a RIM-MAXTRAC
but be aware of the potential power control and programming issues
but that would be the first step
what band to run on and what radio to use
I have done this with numerous radios, but sometimes surgery is required