How to add products to do quotes?

How to add products to do quotes?

Hello . . .  I used to use Zoho e-mail some years ago.  Then I was a way from it for quite a while, but now I have a new business and am jus getting started with Zoho CRM.   I've watched several YouTube tutorials and read some of the online content to get a better understanding of how I can use it.

I'm trying to add products to be able to write quotes and generate invoices but I can't find where you do that.  I saw online where it says " Entering data in the product details form:   You can manually fill in the Product details gathered from various external sources."   and  " Filling in the details in the product creation form".  
But where are those forms and how do I tie them into my accounts?   
Any direction on this would be very much appreciated.
Thank you,
Jack