Hey girl well lemme try to break this down for ya!

Tribal Basics vol 1 breaks down your basic foundation with his Basic Egyptian, Arabic, taxeem, arm undulations (snake arms), choo choo, belly rolls, etc. Pretty essential if you ask me.

Vol. 2 Make-up & Costume
Vol. 3 Zils
Vol. 4 Advanced Workshop: This is the next step in learning ATS. More individual moves such as the Camel Walk, Propellor, Corkscrew, hand floreos, turkish shimmy, egyptian half turn, reach & sit, circle step, torso twist, etc. and of course drilling the moves. Recommended!
Vol. 5 Cues & Transitions; Drills linking the individual steps you've learned by cues & transitions. Dancing with FCBD! Fun!
Vol 6 Improvisational Choreography: Linking it altogether (Vols'1-5) to take to the stage!
Vol 7 Creative Steps & Combinations: 20 new steps & combo's. Just released and highly recommended!

So to summarize, Vol's 1, 4 & 7 teaches the steps & combo's and the others help you to put it altogether (with zils of course!)

I teach tribal fusion bellydance here in Orange County, CA and just got certified in the General Skills program with Carolena and Fat Chance Bellydance. The one thing I find is you have to drill the steps but also you need to also drill with a partner &/or a group to link the steps seamlessly. True ATS is improv dancing with a group. If you're wanting to dance solo ala Rachel Brice, she rarely does any of these steps anymore. It's more about pops & locks becasue doing a basic Egyptian by yourself is not very interesting IMO.

I encourage you to learn the ATS format if you're looking into tribal/tribal fusion. It's a great and essential foundation that is not being studied by upcoming fusion dancers. And since you're already a dancer, these moves will come pretty easy to you so have fun dancing! I hope this info helps! peace.