There are many kinds of Marvel Iron Man Digital Watch with different makers and models. You can try this:
Look at front
of watch right side up. going counter clockwise from left top to right
bottom--consider the four buttons.
light button=A; Mode button=B; Start button=C; Reset button=D
Now follow these instructions:
To set the time, press button B three times. 2) Whatever is flashing
is the area that can now be changed. 3) Use Button C to change. Push
once for changing in increments of 1 unit. Hold for 3 secs for speedy
advance. 4) After completing one change hit D until the area you want
to change next is flashing--refer to instruction #3 to complete all the
changes are made. 5) Press Button B to resume standard time display.