To help your pro anticipate your needs, consider checking your appliance's manual online for needed hookups, connection kits, and other required accessories. If you can, also make note of the type of electrical outlet your appliance requires, the model number, and product/doorway dimensions.
While many Pro Referral pros are happy to provide required items for you at cost, it will help your installation go smoothly to have this information ready when you submit your service request.