Mask in movieclip

i have to make 4 movieclips in the stage and each movieclip must have a different mask.

so i need to make the mask in the movieclips.

now i tried some things but it doesn’t work…

any ideas how i can make a mask in a movieclip, and after that, i have to tween the movieclip from left to right and then it has to disappear.

thx for any help, i’m really desperate