Epson Apex 20020, 20040 User Manual page 121

You can place some 8-bit cards in a 16-bit slot. But if an 8-bit
card has an additional skirt along the bottom (which looks like
an extra long connector), it must go into an 8-bit slot.
If you are installing a video card, be sure to install it in slot 5.
Slot 6 contains the parallel and serial interface and the floppy
disk controller.
To install the option card, follow these steps:
1. Decide which option slot you want to use, then remove the
retaining screw from the metal cover plate at the back of
the slot. (Hold onto the screw as you remove it so that it
doesn't fall into the computer.) Lift out the metal cover, as
shown below.
Put the option slot cover in a safe place in case you later
remove the option card. Keep the screw and washer. You
use them to secure the option card to the computer.
2. Unpack the option card and read all the instructions that
come with it. If necessary, adjust switches or jumper
connections on the card.
Installing Option Cards 5-5