Don't make this hard on yourself. Just watch some YouTube videos. Everyone ignores a few best practices, like wearing gloves, but I've seen worse out in the wild for all of these examples.
You'll also notice that everyone here has a nice studio or a woodshop. It must be nice, right? If you're broke, have a sheet of plywood you can put on milk crates and cover in a shipping blanket. This will give you a semi-decent packing table. Not having to pack everything on the ground is worth the investment. You can lean it up against the wall when you aren't using it and put stuff in the milkcrates. Proper tables are nice, but let's not assume you've got any money just because a gallery is paying attention to you. Broke is the default in the arts...
This guy is okay at this. It will get you through, but he could do a better job. Notice the lack of gloves and the sketchy "FRAGILE" written on the front with a sharpie. The more legit the "fragile" stickers are, the better the stuff seems to arrive. People assume that if you have very clean and nice fragile stickers and tape, you probably have time on your hands and the money to complain effectively. The sketchier the outside of the package, the more slapshot and ill-considered the interior is is the assumption.
There are about a thousand different ways to do this, and everyone has a preference. As far as "right" ways go, this guy isn't it. However, it is a decent enough job to hold up to Canada Post if it stays within the country. Ideally, you'd want to send it a different way than the mail — unless you have never known fear or disappointment — but sometimes you do what you've got to do. If you want the most correct answer to how to do this, check out this page from the Canadian government. It is surprisingly helpful for a government document.
This guy is great, if not a little obesessive. You can proabbly cut some corners safely with a bit more foam and hot glue and get it there about %90 as safe.
Don't build your crate. Unless you have a woodshop at your studio, just don't. It seems like a good idea at the time. "I'll save some money," "I'm pretty handy," "Maybe my friend will let me borrow their table saw...". It is never worth the hassle. It never is. Just pay someone. Eat Mr Noodles for a week, get a gig doing some landscaping, pawn something, sell your stuff on the internet, whatever it is, it is worth it. It is NEVER worth doing this without proper tools. If you have tools, this makes it easier, but if whatever you're doing needs a crate built on premises for it, there are no proper tools, AND it can only be moved out safely without one... You probably shouldn't have done it there in the first place.
If the skater-looking dude in the video thumbnail had just rolled the glassine around the core once before rolling the artwork, he could have avoided that mess with the tape and made the receiver's life significantly easier. Also, masking video is way easier for your client for the internal core. Shipping tape is nice, but the aggressive adhesive is pretty sketchy to put that close to your work on paper.
Staples or Photolab will give you a paper core or two to use as the internal core on a mailing tube. Cardboard outer cores are a little harder to come by, but 4" PVC tubing from Home Depot is reliable and somewhat affordable. The only thing to remember is that the PVC will be dirty inside. Wipe it down with water and a paper towel on the interior, and you should be ready. Also, shove some Ethafoam or bubble wrap in the ends before you get the caps on. It will limit the jostling your work will go through while in transit.