Cottage cheese is one of the simplest cheeses to make and does not require rennet. There are versions that use rennet but I have found that using rennet makes the curds too "rubbery" for my taste.
You can make this with just 1 ingredient - raw milk.
I like to use a ripe clabber culture to speed up the process.
In its simplest form, you can bring warm milk inside, straight from the cow, and leave it in a covered pot on the counter to clabber (this could take 3-5 days). Gently cut the curd after it clabbers and warm the pot SLOWLY while stirring the curds to "dry" them. Be patient. If you keep the temperature below 110 you will preserve more of the wonderful enzymes and probiotics in your raw milk, if you want a very dry, firm curd you can take it up to 120. Pretty soon you'll have little cottage cheese curds that have firmed up nicely. Squeeze a couple to test for texture and firmness, then drain the whey and salt the curds. Add back a little cream if you like.
The clabber culture version is quicker and I think yields better results. Just add 1/2 cup ripe clabber culture to 1 gallon of fresh (still warm) raw milk OR raw milk warmed to 80 degrees. Let clabber (usually faster than above, maybe 24-48 hours) then cut the curds and proceed as above. If you don't know how to start and maintain a clabber culture, that post is here.