I grow and, can lots of vegies, including tomatoes, every year.
Mealy tomatoes means under ripe tomatoes, or store bought, gas ripened tomatoes. Either one is a poor sauce tomato. You can pick them slightly under ripe and, let them ripen indoors for a few days but, the gas treated ones form the store look red but, are mealy, like a blushed or, pink tomato, not smooth and ripe like a red tomato should be.
Make your sauce to your liking. While it cools a bit, sterilize your jars and lids in boiling water. ten minutes at a boil will do it. remove and let jars cool to handle them, leave lids in boiled water until using them.
Fill jars just to the bottom of the threaded part. Use a paper towel to wipe the lips of the jars to be sure they are absolutely clean. place lids and, rings on the jars. Tighten rings finger tight, not over tight. Process in a water bath for 20 minutes at a boil. Use jar tongs to remove jars after processing and set them on a counter to cool.
If a jar is not sealed in one hour, remove the lid, clean the jar lip again, use a new lid and process it one more time. If it still does not seal, store it in the refrigerator and, use within a week. Sealed jars can be stored without refrigeration for up to a year. (Some say or do store them longer without issues, myself included but, I'm erring on the side of maximum food safety here.)
Some will also tell you that tomatoes should be pressure canned, I don't hold with that. They are high enough acid to be water bath canned unless you are using a low acid variety, or adding cream or meat to your sauce before canning.
Then same process except you need a pressure caner and, process (keep under pressure) for one hour. (90 mins if raw meat is being caned and, 2 hours if fish is being caned.)