When the bag you ordered fro TGA arrives, post a pic of it so I can see exactly what you got. There is a shop in my town that sells the super and base soil.
I'll tell you what I did 1st, and then I'll tell you how I'm going to do it differently next time.
I dropped my seeds into a solo cup full of regular cheap potting soil that had been laying around the house for a long time. The seedling popped, and after a few days, once they had established themselves, I transplanted into a 1 gallon pot filled with supersoil, then I put a thin layer of the regular potting soil on top of the super soil as a buffer. Then I realized I shouldn't have puut the seedling in a 1 gallon, but the final pot, so I had to cut the bottom of the pot off of the 1 gallon and plant the pot and all into a bigger pot, full of super soil.
I may be using a different "Complete" soil for my second grow, because I am being gifted a bag of it, and why not. However, when I use TGA super soil again, and it may be the second grow depending on how things work out. But when I do use it again, I will get a bag of base soil, and a bag of super soil. I will fill a 5 gallon smart pot mostly with super soil Then I will make a hole about the size of a 1 gallon pot and fill that hole with base soil. I will drop the seed into the base soil and add water until she's ready to come down.
That's how I did it and will do it next time I use TGA. That being said, I feel there is a very good chance the people who work for the soil company know more than I do about how best to use the soil. I am sure if you make the mixture prescribed by the TGA folks, that you will be successful!