They have pretty in depth info on these nutes and additives on line, good description of how and why. Once you study it a bit, I just started adding them. Still playing around.
They have 3 or 4 different types of base nutes. I've been using the Sensi line, pute likes Connesuer line. Once you pick your base nutes, you start reading about additives.
The base nutes are divided up into two parts, A and B. One has more nitrogen, so you can use equal amounts, or you could use less of one and so forth. I don't use the Veg A & B, soil I use has enough to get through veg. Only cow bell during veg. Begin with nutes at switch to flower.
Bubba