How to make a enemy wave pattern with a spawn?

Hi!
I'm wondering if anyone knows how to make a enemy pattern with a spawn, if without spawn, if someone could please tell me how to make a enemy pattern please!
Thanks!
Tigris
I'm wondering if anyone knows how to make a enemy pattern with a spawn, if without spawn, if someone could please tell me how to make a enemy pattern please!
Thanks!
Tigris
Comments
The aliens have a wave movement there .
Good luck
Roy.