Below is a quote I copy & pasted from the TT thread which briefly outlines how to do it. Two things I do differently: 1) I use vinegar instead of bleach, as the former is less toxic than the latter if you don't rinse well enough. I clean with vinegar ASAP, so the tank/equipment has almost 3 full days to air dry. Air drying is how I "sterilize". 2) I dose with Prazi at the onset of transfers 2 & 4.
TT takes care of ich; Prazi takes care of flukes. So what's left to worry about? Well, there's Brooklynella, marine velvet disease, Uronema marinum, internal parasites and bacterial infections. The good news is all of those have visible symptoms, so you want to QT (and observe) for another month after TT is complete. That is what your permanent QT is for. But it's important to only place the fish in your permanent QT after TT is complete.
P.S. Your final transfer (i.e. Day 13) can be into the permanent QT.