You just add the gun to the cart and proceed to check out. During checkout you'll have to fill in the usual information like your address, payment info and choose an FFL you want the firearm to be shipped to. After the firearm ships and your chosen FFL receives the firearm they will call and let you know it's ready to be picked up. Then you just go to the FFL dealer fill out paperwork for a background check and if you're approved you walk out with the firearm. There will be a transfer fee the FFL will charge for doing the transfer, normally around 20-30 dollars per firearm. Sounds like alot writing it out but I assure you it's not that difficult. Hope this helps.

Super Easy: budsgunshop.com/howtobuy.php
All you need to do really is find a good FFL to have your firearms shipped to. Most charge a nominal fee. I suggest shopping around a little as rates do tend to vary. Then purchase the firearm(s) you want and have them sent to the FFL. I prefer buying online to going into a LGS any day of the week. Here is the buds FFL finder: budsgunshop.com/ffl.php
Stay safe and happy plinking!!

Valdemar, Buds has full guidelines here : budsgunshop.com/howtobuy.php