Bare minimum for a paid wedding job should be 2 bodies with a 17-50mm f2.8 zoom & external flash on one body, and a longer lens (either 70mm ish prime, or a 50-135 f2.8 zoom) on the other. An external flash on that one ideally too. You might need a tripod for the formals too.
External flash has a significant learning curve, not something that takes just an hour or so to master that's for sure. For external flash use you need know how to shoot manual on your camera, you need to understand TTL and how to adjust your overall exposure using FEC, and you need to know how to bounce your flash and the limitations with this approach. There is no shortcut to this, you cannot get away with shooting in auto or the semi-auto modes like Av or Tv indoors with flash if you are using TTL. You also need to understand how to do fill flash.
That said, good luck