I'm no expert, but my understanding is as follows. On results day, you'll receive a score for your DD along with a series of rankings - place overall, place in the South (if that's your priority area) and place for girls in the South. The score was pretty irrelevant for us last year as they changed all the weightings so it couldn't be compared to previous years. However, the rankings is what you need as we know how many places each school has ie if you're in the top 81 southern boys then you're pretty much guaranteed a place at KES.
You then have a couple of weeks to complete the CAF. Even if you're not ranked within the school of your choice's PAN, it may be worth putting it as first choice as this won't affect your second choice if you are unsuccessful. If your DD doesn't have the qualifying score for the GS, that choice will be disregarded and admissions will then look at whether she qualifies for your second choice (score, distance, whatever) and so on. I realise Worcs only has 3 spaces on the CAF so it is vital that one of those choices is a school that you are happy with and know you will qualify for, or else you risk being allocated a school you haven't chosen but has places. If you really want a GS, put them 1st and 2nd, and then the back up high school 3rd.
Come allocations day, the qualifying score for each school will have been set and places will have been awarded to DC scoring above this and residing within the priority area (not always the case in the East, but def in the South) up to the schools' PAN. The letter will also let you know what the waiting list score is; if your DD has scored above this, she will automatically be put on the list and if she hasn't, you can request that she is. But do accept a place at this point (even if its at your 3rd choice) or you risk not having one at all!
Once the acceptance day has passed, and initial allocations has been accepted / declined, then a second round of offers from the waiting list takes place. This will also include high scoring out of area DC, so it is possible to go down the list as well as up
From then on, places are allocated from the list as and when they become available. And of course, you can always appeal.
Like I say, I'm no expert and I'm sure more knowledgeable posters will come along and correct me if I'm wrong. There are details of the past qualifying and waiting list scores in the threads at the top of the Warks forum, but like I say its not always possible to compare year on year.
Shout out if I've missed anything out or if its not clear - and good luck to your DD, its nearly over now