Epson 386/25 - Manual (Page 126)

Once you have determined where to add the memory modules,
follow these steps to install them:
1. Remove the computer’s cover. See page 5-2 for instructions.
2. Turn the computer so that the back panel faces left and the
front panel faces right. The SIMM sockets are located on
the main system board just above the option slots, as shown
below.
5-18 Installing and Removing Options