First step is to procure an alternator. Most people go with a Delco with an internal regulator, fits mid 70's-80's GM products. You will also need the wire harness plug, available at the auto supply.
You will need to fabricate a lower mount. The reason you need the alternator first is to get the pulley alignment right. This is essential, take careful measurements, use straight edge, whatever it takes to get a good, solid, straight fit.
The wiring is simple, search "Delco alternator wiring" under images and you will get the diagram you need. You can reuse the "GEN" wire from the generator, just move it to the "BAT" terminal of the alternator, disconnect the other end from the regulator, then disconnect the "BAT" wire from the regulator, and splice the two together.
You can reuse the "field" wire from the generator, it will connect to the "1" term of the alternator, but remove the other end from the regulator and series wire a 15 ohm resistor or a 12v instrument lamp to the ign side of the ignition switch.
The #2 terminal will simply jump to the "BAT" terminal.