take off left grip frame observe 2 rectangular grey buttons at top and bottom of board
switch marker on
push power button again but within two second (very important) press the lower button multiple times (or hold down) untill you hear a repeated fast paced chirp sound then let go (you will hear a chirp for each level you count down) its very distinctive when you reach the bottom so keep going you will be able to tell)
switch off marker ,next time you turn on = semi
replace grip
reverse for ramping .
RTFM