Check out your local Walmart of major grocer for jars the size you want. Get some lids and rings (they’re all next to eachother) to match. You’ll need a HYOOGE pot to boil water in. Mine is about 14" in diameter and 10" high. You don’t want one that is too tall as you need to be able to reach inside, grab a jar and pull it out - all while managing not to burn the hell out of your arm with the boiling water/steam. You need some sort of tongs to grab the jars out of the water, or a wire basket that the jars can sit in while being boiled. Line your counter or table with towels (hot glass contacting cold counters can lead to explosions). And you need plenty of dish rags, oven mits, etc. to handle stuff and keep from scorching your skin.
Fill your big pot with water until it’s deep enough to cover the jars by about 2". Get and keep at a hard boil. Have your lids on a hard simmer/low boil in a small saucepan and have your rings handy. The key is in the speed you put it all together and boil it. Fill the (washed) jars to about 1" from the top (smaller jars need a bit less space). Use some small tongs to fish a lid out of the water, put it in place and screw the ring on - tight enough to keep it in place and keep the water bath out, but not tight enough to “seal”. You’ll probably want to be using a dish rag to hold the jar and another to hold the ring - it all gets pretty hot from here on out.
As soon as you fill a jar and get the lid/ring on, put it in the boiling bath. Fill the pot as quickly as possible. Boil about 7 minutes.
Use the big tongs or basket dealie to pull the jars out. If using tongs, pull one jar out at a time and place it on the towel lined counter. Crank the ring down hard (but don’t shatter the glass). Repeat until all jars are out.
Repeat with more jars, etc. Gotta keep the water boiling throughout the process. If you need to add more water, wait until it’s back to a full boil before you add jars. Don’t be surprised if you bust a few jars. Between getting the right amount of “crank” in the ring and general defects, it’s bound to happen.
The idea is to fill hot jars with hot stuff, put a hot lid on it just enough to keep the bath out. The bath will further heat the stuff and force air/oxygen out of the jar (you don’t want to over fill the jar so as to have less air to force out though). When you really crank the ring down, it makes the seal. As the jars cool, the lids will “pop”. You know if you have a good seal by pushing in the middle of the lid. If it pops up and down - bad seal. If it doesn’t budge - good seal.
Allow to cool completely. Store in a cool, dry place away from heat and light.