"Shocking" usually just means "getting the chlorine to a kinda high level".

Your fill water looks like it may be easy -- as long as the inside of your toilet tank is not DARK brown / rust color, you should be OK.

If you want to swim ASAP, do this.

#1 - hang the stabilizer in a sock in front of the return. It's slow to dissolve, and you'll lose it if you have to clean the filter before it's completely gone.
#2 - go to a pool store if you have to , but get some polyquat (see www.poolsolutions.com/gd/polyquat.html) and add it AS SOON as you begin filling. It's safe to swim in, at any concentration, but will prevent algae and contribute to sanitizing the water.
#3 - start the pump as soon as you can, and put the sock in place.
#4 - add 1/2 gallon of bleach to the pool the first evening it's full.
#5 - unless something funky happens with the water -- possible if there's something weird in the water -- start swimming the next morning.