I have got notification from zoho website about VAT in KSA is ready now in zoho books

I need explain to how can apply it in my system (Sales invoice and Purchases bills and reports etc...)

And also i need to:

A) Show my company's tax number in sales invoices and purchases bills

B) Show tax number of the customers automatically when i select any customer in sales invoices

C) Show tax number of the Vendor automatically when i select any vendor in purchase bills.

I sent to  support @zohobooks.com but without any responding

Thanks.