The shortlists in each of the four categories will then be selected during January by further online vote of the BSFA mambership - but only works nominated in the first round will be eligible. So this is the moment to ensure that work you enjoyed is not overlooked. The winners will then be chosen from the shortlists emerging from the January vote, by ballot of the BSFA membership and Eastercon attendees.
Apart from being a voter and occasional commentator (though commenting less this year due to my other commitments), I am particularly interested in seeing how this works out, because I am one of the co-sponsors of a proposal to move the Hugo Awards to a three-stage rather than two-stage process - though it is very different in detail to what the BSFA are doing this year and next. (For the detail, see here pages 3-5; for the rationale and debate, see here page 101-103 and 109-114.)
Our proposal was passed by the WSFS Business Meeting at MidAmeriCon II in Kansas City last August, and to come into effect must be ratified by the next WSFS Business Meeting in Helsinki at Worldcon 75 next August. There are a lot of other changes to the Hugos this year, particularly regarding the nominations process (see my summary here), and the outworkings of these changes will probably be the main elements of the debate on whether to take the proposed three-stage voting process forward. But the experiences of the BSFA's three-stage ballot will also be very relevant.