What kind of tomatoes?

Sammy - all the info you need can be found at NCHFP for starters. I'll link it for you below.

Freezing them is no problem. I prefer to core them first since it is easier but it isn't required. You can do it when they thaw and you are removing the skins.

As to how to make sauce - there are many ways to do it if you mean to use it for fresh eating - a blender work fine if you don't mind seeds in it or you can just cook it on top the stove after straining out the seeds. If you want to can the sauce after making it then another set of guidelines will apply so we need to know what your plans are.

As the tomatoes thaw let them drain in a colander to remove much of the water.

Roasting is another way and gives you a very different taste.

Lots of recipes for making tomato sauce are also available over on the Cooking forums and Recipe Exchange forum.

Dave

Here is a link that might be useful: Tomato preserving instructions