How do you enter cheats for commando?

for black ops you have to get out of your chair then find the computer hold x "for xbox" if u know cheats already then just put them in thes a little keyboard in right top corner.(to get out press LT and RT back and forth)

for modern warfare 1 you have to collect Intel and complete the story mode then you unlock them according to how many pieces of Intel you have collected

and i don't think there are cheats for the others