Unclip the 4 pin from the 20 pin virtually every psu is adaptable like so
The next issue is to get enough Molex or Sata plugs to power everything given the age I would assume you would need molex which are these
SATA is the newer standard
The final thing is the cpu power which comes in either a 8pin or 4 pin form factor most psu's have them either clippable together or one is extended off of the other. The port for this is by the backplate connectors on the edge of the board.
I assume that you don't have a modern gfx card that needs an extra power supply