It's the first one on there on his site. You trigger it by making some kind of output set off the logic_relay "xenmaker#_make". You can place as many of these as you want in a map as in place of the number, it renames everything and all the outputs automatically.
Couple of things you MAY want to adjust is light and beam color for diffrent effects, if you say like want a blue one for combine teleporting in. You probably will want to adjust the enemy it spawns, as it's only a headcrab when you place it in the map, and you may want to remove the physics explosion in the case that you really don't want that to happen.
Finally, place this in your bin prefabs folder as you would any prefab, blah blah blah, remember to bspzip that sprite and those sounds, blah blah, enjoy... DeathByNukes gave us full permission ot use these.
I take my hat off to the creater!