Here are some basic instructions for preparing and filling jars, handling lids, and processing filled jars in a boiling water bath canner.
Wash the jars, lids, and bands in hot, soapy water; rinse and drain. Fill the canner with water and place the jars in the rack. Cover and bring to a simmer over medium heat. Reduce heat and keep jars hot until you're ready to fill them.
Put the flat lids in a saucepan and cover with water; bring just to a simmer over medium heat.
Do not boil. Reduce heat and keep them hot until you're ready to use them.
Put the screw bands near your work area. There's no need to heat the bands.
Prepare your recipe for jam, jelly, pickles, relish, etc.. Have a trivet or rack ready in your work area for the hot pot.
Working with one jar at a time, use canning jar tongs to remove jars from the hot water to your work area. Fill jars with a ladle, leaving the appropriate amount of headspace (see your recipe).
Note: A canning funnel is a great tool for this step.
Slide a small nonmetallic spatula or plastic knife around the hot mixture to remove any air bubbles. Using a damp clean cloth or paper towel, clean jar rims and threads.
Center lids on jars so the sealing compound is in contact with the rims. Screw bands down just to fingertip-tightness. Do not over-tighten.
Note: A magnetic lid lifter makes it easier to remove lids, one at a time, from the hot water.
Processing Filled Jars
Return filled jars to the rack in the hot water in the canner. Lower the rack and adjust the water level so there is at least 1-inch above the tops of the jars.
Cover the canner and bring to a full boil. Once the water is at a full boil, begin timing the processing time required by your recipe.
Turn off heat, remove cover, and let jars stand in the water for 5 minutes. Using the canning jar tongs, remove the jars to a rack or heavy towel to cool. Do not tilt, turn, or dry, and do not disturb the lids or tighten bands.
After 24 hours, check for seals and remove bands.
Refrigerate any unsealed jars and use within a few days, or reprocess, heating the liquid again (according to recipe instructions) and canning in sterilized jars with new lids.
Label properly sealed jars, wipe the jars and threads clean, and store in a cool, dark place. If desired, the bands can be washed and saved for another canning project or you can screw them (loosely) back on the jars.
From Food Preservation Expert Sean Timberlake, a few updates (2014) by canning jar makers might save you a few steps.