Oh hey. This page is a brief overview of the basics of water bath canning (as opposed to pressure canning which is totally safe when done correctly but terrifying for some people). Read on below and feel free to ask questions in the comments.
This original source material is pulled from Slow Food Chicago's canning classes handouts.
Step-by-Step Water Heat Processing
(Do not skip a step. It is extremely important to ensure safe and sanitary home canning.)
Clean the jars and closures: Wash jars, lids, and screw bands in soapy water. Discard any jars with nicks or cracks or uneven rim surface. (Washing the jars in the dishwasher also works)
Heat the Jars: Put jars in large stock pot or canning pot, fill so that water covers the jars, cover the canner and simmer the water. Do not bring to a boil. Keep jars hot until use unless the recipe states otherwise.
Prepare closures: In a small saucepan, place flat lids, cover with hot (not boiling) water (new lids with BPA free rubber rings should not be boiled as the older flat lids were). It is not necessary to heat the screw bands. Keep lids hot until use.
Fill Jars: one jar at a time, take jar out of canner and dump water back into canner. Ladle prepared food into jar (I like to use a funnel), leaving the amount of head space that the recipe calls for. With a clean paper towel, clean around lid. Using a magnetic lift lid from hot water and screw on with screw top. Using your fingertips (not wrists) screw lid. Over tightening may cause seal failure. Bang very lightly on surface to get out air bubbles.
Heat process the jars: Put full jars back in canner, fill with water to 1 inch above jars, once the water is boiling see recipe for specified processing time. (I usually keep a kettle of water ready to top off the water if necessary)
Cool Jars: turn off heat and let jars sit for five minutes. Place the jars carefully in a box or pan lined with a towel to insulate the jars for the next 24 hours. Try not to disturb them.
Check Your Jars: After 24 hours, check to see that the jar is vacuum sealed (there should be a u-shaped dent on top of the jar. If it has not sealed, refrigerate and eat promptly with-in two weeks. Be sure to date your food, and if sealed properly, it can be stored in a cool dark cabinet for one year. Remove the ring during storage.