Welcome to TFP! Good to have you here
You can leave everything as-is and test anytime you like. I hope you're considering a switch to liquid chlorine. Here's a couple of links, including one that describes TFPC and the other has the complete testing instructions.
TFPC for Beginners
Pool School - Extended Test Kit Directions (note that this includes OTO chlorine which we generally just use a a spot check for "any FC at all". The one we report here is the FAS-DPD test which uses powder and then drops.
Come on back and report your numbers here, looking like this:
Example only
FC 3.5
CC 0.0
pH 7.8
TA 100
CH 300
CYA 50