The only way to place an advance or proxy bid is by emailing me.
All details are on this page and in the terms and conditions at the start of the catalog:
http://www.ccgtcc.com/auction.html

To clarify the difference between advance and proxy.
An advance bid is put on the book immediately, at the next required increment, and then increased to the next step(s) only as and when other bids are received (ie like ebay, or any live auction house)
A proxy bid is not looked at until the live auction itself. Then, it is executed in the same manner as above. Of course, unless they are relatively high, most proxy bids have already been exceeded before we get to that stage.

If we want to get technical, there is only one scenario where the above changes.
When bidding ends on the show floor at approx 4pm (we have a little leeway as the auction starts an hour later this year), we prepare a catalog for the auctioneer showing the current starting prices for the live auction.
While we are doing that, I look at the advance bids I am holding that are not yet at their maximum, and I look at all proxy bids.
If I have an advance bid and a proxy bid on the same lot, or two proxy bids on the same lot, then I immediately mark up the starting price to whatever it needs to be that leaves just one bid running. All that does is minimises the work (and chance of error) in the auction room for the auctioneer and myself.

Remember that the bids take precedence in order of receipt. Given that on cheaper lots it is not uncommon for there to be multiple bids at the same amount, so it can be important.

Similarly, on the rare occasion that I have two proxy bids on the same lot for the same amount, the earliest gets it. In that scenario though (as has happened once this year already) I contacted the bidders concerned to alert them. (one increased their bid by one step and one did not).

Hope that covers it.