Sherry, boiling water bath canning

Sherry, you need a large, deep pot with a lid and a rack or folded towel in the bottom to keep the jars from breaking. The pot can be a commercially bought canner (those big blue speckled ones for about $15) or a tall stockpot. Place your filled jars with the lids on in the pot that has simmmering water that comes up over the tops of the jars by 1-2 inches with the water. They won't leak, it is fine. Turn the heat up, bring to a full boil, and boil for the processing time in your canning recipe. Jams are 10 min. If it says 5 min. then you need to boil the jars before you fill them, but, it is easier to just process for 10 min. The 10 min. time allows time to kill any bacteria. At the end of the processing time , remove the jars and set on folded towels to seal.
When you invert, you only get a weak seal and nothing has been done to preserve your foods. No bacteria has been killed. Your jam will be OK unless it comes unsealed or molds. NO other food would even be safe to eat if you did that to. It is the high sugar content and high acid in the jam that will allow you to still eat it w/o becoming ill.
Buy yourself some canning jar tongs to keep yourself from getting burned. Cost about $6 here.