I will show you how I converted a florescent Marineland light fixture into and led light
Step 1: Disassembly
with the fixture upside down After removing the light bulb remove the screws facing up. The other two have a nut and can be after you remove the reflector. then remove the ballast but leave the switch
Step 2: Wiring
After locating a suitable power supply, wire are one side of the circuit to the switch and the other straight to the power supply. My choice and power supply was under the maximum voltage choosing one with a voltage too high might damage the LED circuit. Also the strip that I bought was 6 feet long and the fixture was 3 feet long so I cut the tape and half and soldered very small jumpers to the second half of the tape. It was clearly marked positive and negative if yours is not test before you solder them together.
Step 3: Finishing Touches
When wiring is done and cool I remove the tape backing and stuck the strip directly on the reflector. Then the only thing left to do was put it back on the fish tank and push the button