Solder the RGB LEDs.
Cut the leads only long enough to solder, then insert into the PCB holes. Start from the inner-most circle, one circle at a time. I recommend soldering only one lead per LED first, check the seating/positioning of the LEDs before soldering the rest of leads.
Pay extra attention to the orientation – it’s quite easy to put them in backwards (at least for me). Flat side of the LEDs face towards the center of the board. Once all leads are soldered it’s very hard to adjust the positions.

Published April 9, 2012 at 1077 × 1077 in Aurora 18×18 Assembly Guide