Use waypoints if you just want them to be dumb. Set their start position and mark it as a variable eg pos1. Write a loop that checks if they have reached pos2. To do this you may have to increase or decrease an x, y, or z position. When they reach pos2 then set this as their current point and then do them same for pos3 and so on...
Make sure after the last point you add a loop to bring them back to pos1 and then your enemy will repeat it's movement until such time as you code it to do otherwise.
I don't have any code to hand for you I'm afraid as the last version of something similar to this I wrote was in blitz basic(for a really basic pacman clone).
Hope this helps ya...
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