Can anybody explain the process of buying a gun from GunBroker?

Are you asking how you bid or how you complete a transaction? You either bid and win or simply buy something depending on what the item is and how it is listed. If you win, you need to do a transfer through an FFL. Assuming it's a gun and not a knife, flashlight, etc.

I may be missing whatever it is you're actually asking about, if so could you clarify?

First of all, you're not buying from GunBroker. You are buying from the dealer or individual listed as the Seller. Also, GunBroker is NOT a way around local restrictions -- if the gun is one that is not legal in your locale,or if you are for some reason not eligible to possess the gun, you are legally out of luck.

Two key items:
1. Know the gun you're buying;
2. Know the Seller.

Now obviously, you're not going to have any personal knowledge of this particular gun, or this Seller. But, you should be familiar enough with the make/model involved to have some knowledge of how much it should cost, plus what salient features should or should not be present. Study any pictures thoroughly. Ask for more if the Seller has them, and ask questions about the gun. Don't be shy -- if the Seller hesitates or fails to answer, this is a good indication that you may need to move on. Check the Seller's feedback -- there's a sorehead in every crowd so don't be too put off by one bad feedback out of many positive ones. Beware if there is no feedback, and beware if there are several bad feedbacks, or a pattern of particular complaints.

Place your bid. I usually bid as high as I'm willing to go, then bid no more. Keep in mind that in the end you will also be paying shipping and some transfer fee to your dealer. If the present bid is, say, $100 but you are willing to go as high as $350, bid $350. Immediately, your bid will show as maybe $110 -- just enough to beat the current high bid -- and will rise to your maximum bid as others bid higher. If you end up high bid, you win. If you are outbid, better luck next time.

Before you ever get started, find a dealer willing to receive the gun and transfer it to you. When you win, contact the Seller ASAP by phone or email, arrange payment, and let him know where he'll be shipping the gun. Get a signed copy of your dealer's FFL, and mail it to the Seller. As soon as the gun comes in to your dealer, he should call and let you know it's in. You then go by his place, fill out the paperwork, and you're done.

Thank you Pisgah. You answered my question completely.

Gunbroker has an excellent tutorial page that covers the basic. The key is to buy from sellers with solid feedback.