putting a hydro pump on..flushing process both wheels?

[mowisme]

I'm putting on a used pump tomorrow with hopes it's ok. if not I'll have 2 for rebuild/reseal. Can you tell me the process I need to do after mounting it? Do I just prime the pump and flush out that side wheel motor or should I flush it out somehow and with how much oil? what about the other pump and wheel motor..should I unhook those two pressure lines and flush that motor too? what about other pump?..sorry so many questions but I only did it once and that was years ago on a single pump. oh- one of the yellow return lines I had to cut (5"piece) to get it off, can I get this hose at local auto store.. THANKS