I learned to sew from my mom, but we didn't have a sewing machine in the house so we did everything by hand. It's a lot of work, and most people only hand-sew when they have to, but it's a good place to start. Hand-sewing helps you learn about the different types of stitches and fabrics in a really hands-on way. Then, when you start to use a machine, you'll be really familiar with the way material responds to different stitches and needles.
This tutorial by All Free Sewing is great, because they talk you through the different types of sewing supplies, and a few different techniques. If you're just getting started, check this out. They demonstrate the difference between needles for sewing machines and needles for hand-sewing, teach you how to thread a needle, and they also walk you through a running stitch. Their explanations are simple to understand.
This is a great demo for beginners. If you want to learn more about how to stitch, The Brass & Mortar Uniform Depot and Tailoring Shop has a great video for you. They talk you through the mechanics of hand-stitching, and go into the benefits of hand stitching over machine stitching.
DraperyIdeas has a great video series about hand sewing. This video features a bunch of different hand stitches, and explains the ideal circumstances to use them. Check this out if you're confused about the difference between different stitches and want to see them in action.