Unfortunately, not all standard headlight wiring systems are wired the same, so "plug and play" is false advertising. I can sympathize for what its like working with wiring, it's not my forte either. With a little patience, a 12v bulb tester ($6 at any auto parts store) some black and red 12-14 gage wire, and some crimp connecters, you can figure this out and make it work.
1st step is to confirm the LED lights work and what prongs make them work. If there isn't a diagram that shows it, you'll need to test and write down witch are the ground and positive terminals on the back of the light. If lights are both high and low beam, figure out witch prong is witch and write it down.
Use a piece of black wire, strip the ends and connect one side to any bare bolt to ground on the chassis, fender, or radiator mount. strip and connect one end of the red wire to the red positive battery terminal. Don't forget this is a direct connection to the battery. For safety, only strip a small bit of the positive test wire to expose just the ends of the wire and cover it with an un-crimped connecter when not using it. Only touching one prong on the back of the LED light with the red wire, then brush the black wire to all the other terminals to see if the light comes on. if not, take note of it and switch the red wire to another prong and do the same thing. Once the light comes on, see if its the high or low beam, and write down the polarity + or - of the prongs that made it work. If none of them work, check your ground wire. Chances are there will only be one ground prong and the others are High or Low positive.
Second step is to modify the 510s plug wiring to match the LED headlights.
510 headlights use Switched-Ground Wiring rather than switch positive like most other cars.
That means the headlights are not permanently grounded as in newer cars. 510's headlights are permanently connected to HOT positive from the Fuse Box and the Relay switches ground on and off for High beams (all 4 lights) Low beams (2 outer lights). The relay does not switch the 12V positive either. Again it switches the GROUND wires. The relay coil is powered by the GL wire from Light Switch and switched by the BR wire.
On the 510 only the outside lights are both high and low beam so the plug has three prongs while the inside lights are only high beam with two prong plugs. If your LEDS are both high and low, I would put a three prong plug on both giving you four low beam lights. Two pointing forward and 2 pointing outward for greater coverage. In Cali you don't have any safety inspection so no sweat.
On the plugs the Red and White wire is the constant positive on all the lights and the solid Red wire is switched ground for the high beam. On the 2 outside lights the Red Black wire is switch ground for low beam.
Once you have the correct + - polarity and high low position of the LED lights you can modify the stock plug wiring to make the LEDs work.
Best of luck man.