When doing applique, if you don't want the edges of the fabric to show, how do you turn the edges under and sew them? I do believe I will be sewing by hand.

My best advice is to do a search here on applique. There are many different techniques to needle turned applique.
Or if you have high speed internet, search YouTube, there are many tutorials there too.
Then practice different ones, and see which work the best for you :D:D:D

Definitely do a search for different styles of applique. Personally, I like needle-turn, where you turn the seam allowance under just before taking a stitch, rather than turning it under and basting or starching before starting to stitch. I find it's less time consuming and more take-along-able (which seems to be when I do most of my applique - when I'm somewhere else or watching tv - it's idle work for me).

I just did a search on Applique here on the board, and there were quite a few posts for tutorials that were in the Links and Resource section. Maybe some of those will help get you started :D:D:D

I do mine with freezer paper bonded to the back. It is cut one fourth inch smaller than the fabric so I have a guide of what I want to fold back.

I do mine with freezer paper on the front, cut exactly the same way.

You'll find your method, just take a (long) look around, and ask as many questions as you need!

I have also sewn the piece to fusable interfacing and then made a slit, turned right side out and ironed it to the backing. I made a Sunbonnet Sue this way and used invisable thread to attach it to the backing. You could also attach by hand. HOpe I explained this so you can understand. If not, I'll try again.

that's turn needle applique. you may want to google it.