I realise that there will be a few on here new to gardening, and may not know what to do with a glut of tomatoes (I also realise there are many who do, & can come up with plenty of ways to preserving them). I use this for pasta dishes, soups, stews etc, anything you might add tomato paste or a tin to.
Here's what I do:
Wash them, can cut them in half if large, or leave whole. Remove stalk.
In a pan large enough to hold them, with space for simmering, add sufficient water to cover the bottom & add toms.The water stops them catching, if any burn they will taint the lot.
Slowly bring to the boil, bringing the ones at the bottom to the top.
leave to simmer for about 1/2 hour. Stirring occasionally and squishing them on the side of pan to help break them up.
Either use a vegetable mill to remove the seeds and skin, or use a sieve and a wooden spoon to squeeze the liquid and pulp out. You may have to scrap pulp of the bottom of the sieve. Make sure you've put a bowl underneath to catch the liquid! (I've forgot this before).
Swill out the original pan, and add the liquid to it. Bring to the boil and reduce to thicken, stirring every now & then. You can slowly take it down to a paste, but be careful not to let it burn.
pour into sterilised pots, and add lid. It will keep for a few days in the fridge, or months in the freezer.
I don't add seasoning, and find the final result is quite salty anyway.
Hope this of help to someone.