Preparation before soldering, in addition to the iron, 5050 smd and pcb board need to be heated to the appropriate temperature, will be soldering LED PCB pad clean, wear goggles, put the solder paste into the solder joint location and heating the solder joint to melt the paste, use tweezers to pick up the 5050 SMD LED to the appropriate location, the tip of the soldering iron on the end of the LED, and then remove the tip of the soldering iron, LED should be left in the PCB, fixed to wait for the natural cooling of the solder joint.