There are two methods to fill your manicotti shells. The first is to use a small spoon to fill each piece of pasta. The second is to put the meat and cheese mixture into a piping bag, and snip a large hole in the end. Pipe the filling into each shell. If you don't have a piping bag, you can also use a gallon sized freezer bag in the same way. I prefer to use the piping bag method because it's easier with less mess at the end.