Unpack the LED pack. (LED stands for Light-Emitting Diode)
There are 8 LEDs to insert. LEDs need to be inserted the right way round; otherwise they will not light up! This is very important because all you need is one LED to be inserted the incorrect way round and most the LED's and IR LEDs will be effected by this in one way or another. It will take a long time to find the fault if you do something wrong here - we have some experience with this too :-)
One leg is shorted than the other leg. This shorter leg is the '-' side (cathode) and needs to be connected to the square shaped pads. There is also a flat face on the case of the LED casing (just visible) to indicate the cathode side. You can also see inside the plastic casing which leg is the cathode.
Ensure that they are straight. Double check all LED's that they are the correct way round before soldering. Remember square pad = short LED leg !
Cut the legs off with the wire cutter. Be sure to wear safety googles as the leads can shoot off at speed.
The completion of Step 3