Best practice : when to convert lead to Deal

Best practice : when to convert lead to Deal

Hello,
I'm new to Zoho and run my own business.  To make sure I'm using Zoho correctly, when do I press convert, from Lead to Deal, at what stage in the conversion funnel/conversation. 

I want to make sure I can a) monitor status of all pending lead or deal  b) generate proper reports for tracking business marketing.    Leads come from a contact us form on my website: they can be junk/spam, or legit.  If legit, I use Lead status such as joined, verbal commitment, no show, unable to reach for lead status.   I get confused between Lead tracking versus Deal tracking and what is Zoho best setup for when reporting.  Under deals, I don't see leads status which is what's confusing.