Epson 386/25 - Manual (Page 41)

Slide the diskette into the drive until it is in all the way.
Then turn the latch down to lock it in a vertical position.
(For more instructions on inserting and removing diskettes,
including 3½-inch diskettes, see Chapter 3.)
3. Turn on your system. (Remember to turn on your monitor
and any peripherals before you turn on the computer.) The
screen displays the Operation Menu:
If an error message appears when you turn on the computer,
see “Continuing From an Error Message,” below.
Running the Setup Program 2-3