Your first project should not be difficult. There are plenty of kits available with printed design on the fabric. Often these come with embroidery thread, as well as a stitch guide, so you don’t have to work hard at finding something that is fun to do, as well as being doable.
Samplers are a good way for beginners to learn different stitches. Don’t be afraid to learn new stitches. There are lots of videos on the Internet that show you how to do just about any stitch. However, don’t get hung up on learning lots and lots of stitches. You can do an entire piece using just one or two stitches. I’ve done plenty of pieces using just the chain stitch!
Fabrics for embroidery can really be just about anything. However, I always suggest linen, especially for beginners, simply because the fabric is a little looser, so it makes the needle and thread go through easier. After you get the hang of it, you’ll be able to embroider on most fabrics.