Plug them in with the four black wires in the middle. It is pretty easy if yuo angle them in there. See your manual to make sure the jumpers are correctly set. For ISA cards,pop it into one of those black one that is the same size. For PCI, plug it into the white slot.
Most cards fit inthis same manner.
Plug the your monitor into the video card ,and plug the computer into the wall, and flip the swtch. If you followed the simple instructions that I laid out step by step , your you should have a working computer. If not, go back and trace alll the instructions. Plug the in a card ,just like you did with the video card. Your motherboard shoul have on board floppy controlers.