Random Dot Patterns - ViSaGe??

Hello!

I'm a bit of a MATLAB novice and I've been asked to produce random dot patterns for motion coherence testing (i.e. we can control which percentage of dots are moving up/down at any time). We have a ViSaGe VSG card so I'm told it should be relatively simple, but I have no idea where to begin and would appreciate some assistance.

Thank you!