How would you learn to reload?
1- First, read the information on relaoding metallic cartridges in the front of some reloading manuals, especially the Lyman Reloading Handbook and the Hornady Handbook of Cartridge Reloading.
2- Then, start out by getting a press kit and dies for a cartridge of your choice (pistol cartridges work well to learn on, but rifle cartridges are OK too).
3- Then study the mid-range loads published in the reloading manuals, purchase bullets, primers, and powder, and set aside some time to set up the press and get familiar with it and how it works.
4- Then, being careful to avoid clutter and chaos on the loading bench, try reloading a few cartridges to the specs stated in the loading manuals.
5- Then take the cartridges out and fire them in your gun. Do this several times until you find a load that performs well in your gun.
6- By now, you will be starting to understand a few basics of reloading. Load a supply of one or two boxes of ammo for your gun (don't load hundreds of rounds, taking them apart is a pain).
Read more, learn more by talking to knowledgeable relaoders, and keep it small initially. After a few years, you will know a bit more, and you can build on it.
Good luck!!