The TD's are always the first weekend of the month, usually starting Friday - holiday or not. THP will likely be gracious (as always!) and post a link to the official thread on this thread, since it's where most of the banter (a.k.a. "smacktalk") has occurred. When he posts the link, he'll also post the official rules, which will include "proof of life." The proof of life is a money amount - less than $1 - which must be included in at least one of your pics to prove you made the entry for the TD. Some people post a "teaser" pic - ingredients that will go into their creation - and put the proof of life into that. THP will tell us in the rules if a teaser pic is necessary or not. Some people post "production" pics - pictures of the process - which aren't usually required, but may help garner votes. Finally, you
must create a single post for your final creation, which includes pics of the final product, recipe (measurements are not required), and proof of life if it wasn't included earlier. Some people post teaser, production, and final pics in a single post.
When THP posts the official rules on Friday (time of day varies, so be on the lookout for it), he will also tell us when the contest will be over - typically some time Sunday. If a holiday occurs around the weekend, the actual days may vary. Based on what I've seen, we're talking U.S. holidays. THP will post another thread some time following the end of the entries, and that thread will contain the opportunity to vote. All members of THP can vote, even if they didn't submit a TD entry.
I recommend looking at some of the past TD threads to see what you're up against. Your Australian BBQ Association membership will get you nowhere!