There is a start-up kit, private labeled for HotSpring. It contains pH up and Down, Dichlor, MPS, test strips, Stain and Scale Control, and one or two other things that my brain can't bring up just now.
Your dealer may give you that in addition to the AG+ Silver Ion Cartridge, or they may simply put together similar items off the shelf.
You MUST have:
Testing device: kit or strips.
pH adjustment. Some dealers only include the one you'll need most often.
Sanitizer: Dichlor, Bromine.