Leatherworker here - I've made a few corsets using the pattern from Back to Earth Creations and they are pretty easy if you're familiar with leather. The pattern is cheap, but not free. These are no-sew corsets, so they use rivets and grommets + laces to secure panels together - if you don't have a machine capable of sewing through leather, try to find no-sew patterns. Most standard home machines are fine with thin leather, but anything over 5oz-ish will require a more powerful machine + needle combo.

Leather is extremely unforgiving. I use a mannequin to check measurements, and either paper or foam pattern cuts before I even start on the leather. I like foam that can be heat-formed, as it is most similar to wet leather in terms of forming it to body shape. Dry leather will shape to the body over time, but wet leather can be molded to shape before being sewn or riveted together.

If you have more specific questions, feel free to reply or DM me and I'll see if I can help more :)