Random Unit Groups

So, I went to Advanced > Random Groups and made myself a couple unit groups and sets, but how do I put them in game? It doesn't like it would be that hard, but I cant find any place to put them in. Unless it needs to be done by triggers, I haven't actually checked those yet because it seems like there should be some easier way. If I was going to use triggers I might as well just use a random number and use that to choose what units to spawn. Anyways, if anyone knows how to put these random groups into the game that would be nice. Thanks for the help.

That tool palette has some units with question signs called random units, place one then double click it and it should get easy after that

ahh, you double click on him! Thanks alot, I knew it was gonna be easy =P