wow, that's really complicated!!

here is mine (unscientific and CHEAP!! only works if you live near apple trees)
pick apples off trees or ground
Wash
Cut off everything but core and bad parts.Save cores for chipmunks.
Cut into pieces, skin and all.
Add a little water to pot, cook until mushy.
Add sugar to taste.
Put in fridge or freeze.

I just quarter apples, cook with a bit of water, depending on the amount of water released from apples. Put through food mill,(that separates the skin, pits, etc from the fruit) add cinnamon and that's applesauce.

I have a juicer. One side will give the Apple juice and the other side will give a mash of apples. I took the mash and cook it in some honey instead of sugar and cinnamon. Can them after done. The apple sauce turned out to be so delicious and nothing was wasted, Sorry Chipmunks, or in my case goats.

what happens to the seeds?

I just buy a large can of White House apple slices at Sam's Club. Open, pour into a pot with the liquids from the can, add enough water to come about 1 inch below the top of the apples. I add 2 teaspoons of ground cinnamon, cover with an lid, and cook until tender. I then take a potato masher and mash until they are the consistency that we like which is chunky applesauce. You can mash more or use a stick blender to make a smoother applesauce. I add ten packages of sweet and low but you can use sugar if you desire. We always have this in the refrigerator for a snack or to put on pancakes, french toast, or hot cereal. I have made applesauce from scratch but when you put it through the food mill it is way too smooth for our liking and I haven't figured out a way to make it chunky without coring and peeling, which is a lot of work and time spent standing on your feet. Ann in TN