Repeating a movie clip every so many frames

1

i am having some trouble doing something that i think should be pretty easy. i am trying to lay a movie clip on the stage every 600 pxls. the clip is actually longer than that, so they need to overlap, but i can’t seem to get the code right. i only get it to lay the first time, but can’t get it to place after that. can someone push me in the right direction?