Joe, Another one is Lightenupandshoot, I use to videos that Andy does on Layers and Masks when I teach elements. Both of them are funny, entertaining plus you actually learn. I use one of those small fold out soft boxes and a sometimes a larger one 24x36 that opens like an umbrella. What really helps with off camera flash is light meter that will do both ambient and flash , flash only and ambient only. If you use ambient plus about 30% flash (Sekonic L358) will tell you; you just have to remember which power setting you are using and how far from subject. I think I uploaded a couple of my grand daughter with giant #2 which has 30% flash and ambient.
Joe Brady has a lot on you tube just do a search.
Ciao,
Lou Cioccio