Find an expansion slot ideal for your Video Card. The slot must be the correct type, and it should be as far as possible form other hardware in the system. Remove the case insert that corresponds to the slot on the motherboard. This is usually done by unscrewing, but some cases have punch
Insert the Video Card in the slot. You might need to rock the card in, inserting one end first, then rocking the rest of the pins into place.
The old ISA cards may be tougher because of their length.
You might not be able to rock them. When pushing down, make sure the motherboard does not flex. It may be necessary to place one hand underneath the board to hold it up. Screw the card into place. Double check your work.