You book your animals in and the abattoir tells you when to bring them, or if they are collecting the animals too, when the lorry will be at yours. You work to their schedule. Normally cattle are processed on 1 day, sheep on another, pigs on another. If it’s a big abattoir then they may only do 1 species and they will have set days for different classes of cattle for instance- bulls and mature cows on 1 day, prime cattle another day etc etc.
For hanging, the norm is 1 day up to 7. Follow the butcher on that one, they will know what to do.