How to enable inventory & services

Hello, I have taken on a position to run the finances in the company and have not used Sage before, but am now at a level of understanding most of it. However, we sell bulk inventory items. When invoices have been issued, they were done through excel and then prepared in Sage 50 Premium as an sales invoice for the total invoice amount.

I would ideally like to create all sales orders and invoices in Sage. However, the company that has been setup in Sage has no inventory & services available and I wonder how to enable this in Sage so I can create and inventory and item list in order to create all sales orders and invoices in Sage. How do I go about?

Appreciate your assistance.

Thanks.