First thing you need, James, is a book, or two. Casting is its own "subset" of shooting, and has as many quirks and twists as anything else, and more than some!
You will need (minimum) a heat source, something to melt the lead in, a way to pour it, and a mold. Beyond that, it gets a little more complicated. You will need a bullet lube, and a way to apply it (there are different options) but you must lubricate cast bullets or leading results even at low speeds.
Most molds cast the slugs oversize for the desired bore (caliber) by a few thousandths of an inch. The bullets need to be sized for the correct diameter (the actual bore size of your gun). Cast bullets generally need to be .001-.002" larger than bore diameter, sometimes more. Note how this is different from jacketed bullets.
The exact alloy you cast will have an effect on sizing, as different alloys shrink different amounts as they cool.
They make dies for sizing bullets, and Lyman makes a press for doing it, and lubricating the bullets at the same time, but that a bit beyond bare basics.
Cast lead, of the right alloy will get you up to the 1200fps range (maybe a bit higher) without the need for gas checks. Using gas checks the 2200fps range is possible before you exceed the ability of the bullet. NOTE: Bullets are designed for gas checks have a small "step" in the base where the gas check goes. They can be used just fine without the gas checks at lower velocities, where the gas checks are not needed. Bullets NOT designed to use gas checks don't have a place to put them, and so cannot be used with gas checks.
You need to study casting techniques a bit, learn about fluxing the alloy, what different alloys are best for, and general tips. Here's one, wheel weights are a good source of a medium alloy, but take some work to prep. One thing that needs to be done is they need to be washed. Chemicals on the weights (road salt, in particular) do ..not good..things in your melting pot, so keep them out if you can.
Molds are generally either steel, or aluminum. There are pros and cons to both types. Molds need to be at the right temperature to cast good bullets.
Gloves, goggles/face shield, and I recommend a shop apron or other protective clothes, and of course DO NOT BREATHE the vapors!!!
There's lots more, but you can cast perfectly good bullets with a minimum of equipment.