How to bleed coolant?

Okay, this is the cheapest micrometer ever, they sell them at harbor freight for less than $10, but it can measure inside and outside diameter. It's not designed for mechanical measurements that need to be super precise, but it will work for your needs, I use this thing all the time when doing 3D printing. The smaller side facing kind of up on the left side is for taking inside measurements, you can use the jaw side for measuring outside diameter if needed.

Yeah, the rubber hose should be able to stretch enough to fit over the plastic fitting, and then a hose clamp around it. I check out your videos really quick.

Yeah I saw the TSB for the hose installation. It seemed like the basic idea was to have a higher section of hose where any air in the system would be able to rise to and then exit into the expansion tank. Thats why they put bleeder screws at a high point in the cooling system, the issue with the cooling system right now (stock) is that air pockets are getting trapped in a location where there is no higher location for the air to go, technically the vacuum down bleeder method is supposed to take care of that, the downfall I see to the method is some coolant leaks happen under positive pressure and can be missed when its under a vacuum due to the negative pressure, or lack of pressure.

In the 2nd video that whitish section that the hose came off of looks to be about 5/8in or so, you could just measure that with a tape measure, then you'll know the outside diameter of that section you need to fit a hose over and the size T fitting you need. It looks like with that bleeder being there as well, that will now be the highest point for air to escape, even from the expansion tank which will help.
Next you will need to see how big the inside diameter of the hose go to the expansion tank is.

Yes, the hose coming from the heater core hard line was probably a quick disconnect, so just put a regular hose clamp over that once you get the T ready and a short piece of hose to go in between the T and heater core section, it looks like 5/8" to me but measure it with a tape measure to be sure, just remember to run the hose under the air intake boot so any trapped air will travel to the bleeder screw.

It looks like a quick disconnect fitting, some of them that appear to not come out, meaning the part that looks like a clip on the receiving end of the other hose, need to be squeezed together to get them apart, it should clip in when pushed on if its not holding, then the clip is not grabbing onto that outer ring section, if it was bought from an aftermarket location it may not be the correct fit. Parts from amazon and such rarely fit correctly, but it should snap right into place.

Is this a hose that you added and is not stock to the vehicle? That plastic end with the round ring on it is definitely a quick disconnect line, a rubber hose wouldnt go on the end of that, it would be another plastic piece with a clip to secure it in place.

Can you identify the section of hose on this diagram youre referring to, I know it says thermostat to engine. But is it part 19 on the diagram?

Okay, it's supposed to go into that smaller opening in the first picture?

It looks familiar, the plastic tube might be missing a locking clip on it that slides over the end of the tube and is one of those that requires it to be pushed together to get it to unclip and come out. Not sure if I can find a picture of one, I'll try though.

I was thinking of something like this, but it does appear something is either missing or broken off where it goes into that hole, it almost looks like there is a metal insert in that location?

What is this part? If that's a section you can identify, do a google search for that part and see if you can find a picture of the original, then you'll know what might be missing, there has to be something that clips around the end of the that plastic tube to hold it in place.
I found this on a search but there is nothing on that end of it.