You're thinking machine sewing I assume? It's best if you can find someone with a sewing machine to take you through how the machine works and help you try some seams. If you don't have someone to help you, you can check for classes (for instance from a local quilt shop or community center), and acquire a machine to practice with. Some libraries have machines you can use, or get a cheap basic machine from someplace like Walmart. You might also get lucky finding a machine at a thrift shop but make sure it works before buying.

Have you already checked YouTube for tutorials? When I took home-ec back in high school we started with learning how to cut fabric and pin it together, how to properly thread the machine, how to operate it safely (there is a lot of force and moving parts and you have pins everywhere) and practiced sewing straight seams on two layers of cotton. Our first project was a draw string bag. If you want to start really basic you can always do some hand stitching (running stitch) to get a feel for how the fabric behaves and how to piece things, and plus that's a good skill for basting when you are machine sewing.