You are started! Do you have any local leatherworkers that you know from barrel racing? If so, reach out to them. Ask questions here. Check out the sub-forums such as Saddles and Tack.
Finally, if there is a local supplier in your area, do they have classes? I started by having a specific need to make something, just a small item. That has grown into wallets, briefcases, etc. it has been fun, I've learned a lot and through this forum am learning more every day.
Good luck to you!