How do house auctions work?

A very happy seller (2 bed freehold house). We used First For Auctions as the property was not suitable for an estate agents due to needing to be renovated. They are part of the same group as Leaders, (the Romans Group) who asked them to get in contact with me. I found them to be very knowledgeable, affable and they kept us updated on the process every step of the way. Gareth Bell was my point of contact, and he was very good at explaining everything in a transparent way, so that I was kept completely up to date with the weekly email updates and explanations of the markets reaction to the house, and he was always available by phone for any question, no matter how small. I thought we may get less for the house at auction, especially as the reserve was set under what we hoped for, but in reality, the house went for slightly more than its value, and the completion was hassle free in only 6 weeks! As an unconditional auction, it gives the seller total peace of mind, as there can be no last minute buyer shenanigans. I would absolutely use them again, both to sell, and to buy.