1) Check the fuse for the headlamp.
2) If not OK replace fuse and see if it blows again.
3) If OK enjoy the Max and send me beer tokens to the usual address.
4) If not OK use expletives of your own choice. Decide that you are probably looking for a short circuit.
5) Get a wiring diagram.
6) Get a multi-meter.
7) Get more fuses
8) Study the diagram so that you understand how the power gets from the fuse to the headlamp.
9) Trace along loom and check for chafing and when found repair affected wire.