This is how I make the physical zines.
I do things factory style, which means I don't make each zine one at a time, I systematically do all the steps in batches. It's faster, it becomes mindless work, so you can watch TV, even read, or think about other things while you crank out a zillion zines.
2. Staple. Staple first! It keeps the pages straight. I staple them all, and put them all in a pile.
3. Fold using my Zine-Fold-o-Matic(tm) (see below.) It's easier than eye-balling, and it gets a basic fold in pretty much the right spot, and it's not going to cause carpal tunnel syndrome from folding, pressing. Again, stack them all.
|Zine fits between the flaps. Not exactly, but close. You need some play.|
|I bow it like this to make sure it's centered. This is the most important part.|
|Fold! I use my whole hand so I don't get cramps or RSI.|
|Shot Glass for a harder edge|
|Rule for scale, I used a physical zine for the measurements. Four scores. There will be a gap between the edges of the zine and the plastic-folder-thing. This is OK.|
|This is to show the scores. I cut through one side, and only one side. You don't want to make the flaps too big, or it won't fold. Or too small, it'll kinks the pages.|
P.S. #7 is in layout.
Bonus Tips: Get a stamp for your return address and use address labels for the recipient. Writing out addresses separately sucks. I did hand label a few, but if there is more than 1 or 2, I always cut and paste their address into a template, and print.