[Johnny B]

Well dude, this was kind of me last year. I was also worried about getting the mixture correct, and it gets just as cold here as it does in Canada here. 🥶 This is what I would do, and did do.
Like you, I did my coolant change on schedule. This is important because the coolant should be still in pretty good shape, so getting it all out isn't necessary.
Just do a drain and fill from the radiator, twice. Drain it once, then drive the car until it fully warms up, then drain it again. Just use Dexcool 50/50, easy peazy lemon squeezy.
Do this every 4-5 years and you will be golden.

 

[Johnny B]

Dude, you spent 3 hours trying to learn this. Yaaaah right.
You are trying to make this much more complicated than you need to. Just calm down and listen.
#1 I didn't say anything about distilled water.
#2 Yes, just buy the pre-mixed Dexcool 50/50. Do not getting anything else, no universal, no all makes all models, only get Dexcool 50/50. Get 2-3 gallons.
#3 You are to caught up on "flushing". Unless you aren't telling me something, your car doesn't need to be flushed. I've done my own coolant changes for decades, I've never need to flush anything. That is just fancy BS talk from dealerships to make you think they are really doing something useful for the money they charge. Yes, cars rarely do need flushing, but that is usually caused by people that have contaminated the cars coolant system.

when do I bleed the coolant so the air escapes?

Remove the bleeder screw when filling the system, once coolant starts to flow out of the bleeder hole re-install the bleeder screw.

do I just pour the coolant into the reservoir until the fill line?

Yes. After filling it, take it for a short drive, and check the coolant level again. It is almost certainly going to drop a bit, because the system will work out any air pockets.