I'm new - just bought a house with a IG SWG Pool and the something went out (salt cell?)

My wife and I just bought a house built in 1862. The pool was put in about 10-20years ago. It has a vinyl liner and a Hayward AquaRite generator system. The salt cell is a Blue Works T-15. There are some test strips for pool chems and a test trip for salt ppm. Chlorine, Alkalinity, and stabilizer are low I think. Salt looks ok on strip, but display on SWG says 0 and -0 instantaneous. I made a post on what I did to troubleshoot. Nothing yet, just sadly addling chlorine tabs. Hi! Looking to learn how to take care of it.