Hi and welcome,
To get a GP to run you only need a power supply and a clock.
You can run on a high frequency crystal or a low frequency one (32kHz) and the PLL.
If you use the PLL you need additional filter components on the CGMXFC pin.
To program it you can use a MON08 interface or a serial port and a serial monitor.
If you use the serial monitor, you still need to programme this in via the MON08 interface initially.
Probably your first move is to sit down and read the GP32's data sheet which is available on the GP32's product page on this site. This should hopefully answer most of your questions, if not, ask them here.