At DL this is how it works. If we get the VQ it might work similar:
The land opens to guests, the land fills to capacity and the VQ kicks in on the DL app (for us it will be
MDE) On the app it tells you that the land is full but you are invited to join a boarding group. You click join and it tells you an approx time of day (afternoon, mid afternoon, evening) that you'll be allowed inside the land. You can go about your day knowing an aprox time, so you can go do other attractions, eat...
Once your boarding group is called (a notification on the app) you have up to 2 hours to make it inside before losing your spot in the VQ, so let's say you're eating, or in line for an attraction or even your hotel room, you have 2 hours to come to GE.
At DL guests need to have scanned their tickets at either DL or DCA for them to be able to use the VQ, you can e leave the park but first you must have scanned your ticket to enter.
Here at WDW it should work the same, where you can go into any of the 4 parks and be eligible to join the VQ. Every member of your family has to scan tickets, you cannot come in by yourself and then get all of the people in your MDE party to join