Late summer you have a worm count and Worm if needed. (there's an online company who you can post poop to)
Weight gain should be steady, any weight loss could indicate a problem that might make hibernation dangerous, so regular weighing is needed, he weight once a month.
You simulate an autumn if indoors, I have a lamp on a timer, it gradually comes on later and off earlier. I use a hibernation service, its less stress and I don't need to worry about someone leaving him out of the kitchen fridge. Food is gradually reduced and then stopped. Heat and light times reduced, but hydration kept up.
Fridge methods give a steady temp, no warm days to wake them up and no freezing. (also no rats stumbling into a garage and having a nibble)
Length of hibernation depends on age, my tortoise is young and hibernates for a few weeks. They are weighed often to check there's no big loss, and popped back into the fridge.
When they wake up they make their own way to the heat lamp, hydrate and start eating. Ours takes a week to be wide awake before we go to collect him.
He didn't hibernate this year as he was on the lower side of weight for his shell size. He looked quite miserable over Christmas as he wanted to slow down.