when we had our garden and an over abundance of tomatoes. We had boiling water on the stove and you plunge the tomato into the water, take it out and take off the skins......we then put it thru a sieve type colander and get rid of the seeds......then you have the basic tomato puree. You can then add your own touches to it.......we froze our tomato sauce by putting it in quart size baggies and put it flat in the freezer.....worked out well....
I made sauce the other day and had a little hamburg in the base of it with green peppers and onions . Then took out of the casings hot sausage stuff and mixed it with a pound of beef burger and made meatballs .....they were so good.....had to pat myself on the back for those....delicious......
by the way......making sauce is alot of work......and time consuming......we now eat tomatoes and give some away and ....buy my puree and sauce in a can....
have fun