MILD SPOILER WARNING
Once you've unlocked it you can access the "schedule" for the girls downstairs (it is the button on the left of the screen).
After opening the schedule you can then select a girl and the day you want her to work.
Then you select "change task"
This will open up a menu from which you can get the girl to "Stay on Bastet Domain", after selecting that her "job" for that day will change, you will then be able to find that girl in the Domain on the selected days.
NOTES:
- the girls will refuse to work if their mood bar is in the red (You can raise their mood bar by having sex with them)
- Their mood bar goes down if you put them in the domain and forget to milk them (You might also get less milk, but I'm not sure about that)
- The girls produce milk throughout the day (whenever you use energy the amount of milk they have goes up by their production amount)
- They do have a limit and won't go over that limit no matter how long you spend waiting for them to on a single day (I don't think we have a way to increase that for now, but it seems like something we'll get eventually)