In theory it should not be hard. Get hi/lo bulbs. Sockets to accommodate 3 wires. Refit the housings with the new sockets and bulbs.
For the actual wiring, reconnect 1 wire to ground reconnect one to turn. The 3rd wire for running will need to be run to the running light circuit and you should be able to tap into your license plate lightís wire or the tail lightís wire.
I installed extra running and turn signals but I didnít rewire any existing lights. itís pretty simple once you find the wiring schematic on the internet to decode the wire colors.