To build a Tracksoar I highly suggest ordering the boards from osh park and a solder stencil from osh stencils, this will make your life much easier. With those to items in hand order your BOM, most of which can be purchase from mouser. The only exceptions are the radiometrix transmitter, GPS receiver, and LTC3426 boost regulator. You will also need some solder paste to make life easy.
Supplies in hand squeegee on your solder paste using the stencil and place components. You'll need a decent set of tweezers and some sort of magnification. Once the parts are placed either put it in a solder oven, use a hot air gun, or skillet to reflow your solder. THis board has SMT parts on both sides so the back will have to be done by hand as it has the easiest components. Once the board is assembled we can flash the bootloader.
You'll need an AVR programmer such as the AVR ISP mkii or dragon to burn the bootloader. The ICSP headers are broken out on the Tracksoar and a programming shield is available to make life easier. Select your bootloader and burn it and you're ready to program your Tracksoar using the Arduino IDE.