How do you Assign a SALES REP?

How do you Assign a SALES REP?

Hello,

New to Zoho, a couple of quick questions,

in CRM
How do you assign a sales rep?
Is it possible to assign a sales rep at the time of creating a Sales Order?
do CRM sales orders integrate to Books Sales Orders?
Are Invoices required for a new Sales Order?

BOOKS
How do you assign a sales rep in Books
Is it possible to assign a sales rep in Books when creating a sales order?'

Thank you,

Jeff