Sounds like Peg got you on the right track! Ball and the other canning companies have good info that is super helpful and easy to follow.
Cleanliness and proper acid content is key to prevent spoilage or bacterial growth: Sugar content prevents spoilage, as does acid (lemon/vinegar) so following a recipe is important, until you have some experience. For instance, newer tomato varieties have less acid, so you would need to add more acid when canning a salsa for instance, to achieve for a safe ph.
My parents canned lots of stuff, from vegetables(low acid) and wild game in a pressure canner to jams & fruits in a water bath. I now make salsas, jams, condiments and use a 10 minute water bath canning. (I don't do the "put a lid on it and turn upside down" method, but my mom did use paraffin with jams)
- Clean everything. dishwasher is great. Soak lids hot water
- Pack jars with hot mix
- Wipe rims, go around the inside of the jar to remove bubbles with a knife
- add lids, rims, finger tight
- Process 10 minutes
- remove & let cool, Have fun counting the "pops!" as the lids seal
Washington State University has a great online resource of recipes & canning info! Their salsa recipes rock
https://extension.wsu.edu/food.....n-canning/
Have fun! There are lots of new books on canning, including low/no sugar added methods, more variety in complex flavors, and then the whole fermenting world.
"Canning for a New Generation" is one book I have that has lovely recipes. I've never gotten sick, or had any spoilage. & the ole "when in doubt, throw it out" works as a good reminder, I have tossed 3 year old jars, as color & textures change.
Love my fig jam with cheese! & fig jam on pizza with prosciutto....