Rondog, pretty much. You can call and they'll take your information, or you can do it online. I did mine online, in the checkout process it will give you a list of FFLs it has on file near the zip code you put in, so you can either select one of those or email a copy of your FFL.
Buds charges 3% on credit cards, so if you want the cash discount you can either do an electronic check or send one in through snail mail. However, the fine print doesn't reserve you a used gun, basically they can sell whatever they've got till your funds come in, which n a deal like the 3" K frames, they're so popular I don't think they'd last long enough to get the check to them.
Once you pay and select or send an FFL, you wait for them to process and ship it. It's is what most people complain about, as it can take a while for them to do it. A week sometimes, sometimes more. So you wait...