When using granite it must be templated (measured and a template created) onsite.  In order to make this process go smoothly, you should have the following:

Cabinets installed in place

Sink to be installed onsite, if using an undermount sink they may ask to take the sink with them to the shop.

Appliances

Faucets – make sure you know where you want this located as well as other items (soap dispenser, insta-hot, disposal button) so that holes can be drilled correctly.

By having products onsite you can prevent unknowns, re-dos and delays in the schedule.

Ask them how long the fabrication will take, you should expect 1 – 2 weeks.

Good Luck!