leads and potentials

leads and potentials

Hi, I have an Excursions and Activities Travel Agency. My current sales process goes like this.

1. Customer (individual) fills out info on webform, info gets transferred as a lead.
2. We qualify/verify the lead and email client basic template.
3. Send Followup template if no response by certain amount of days.
4. Confirm the availability of activity that the client wants to book.
5. Send Invoice Quote
6. Verify Payment and Followup
7. Send information over to processing.

So the questions that I have are:

a) At what step of my sales process do I convert the Lead?
b) When I convert a lead, do I create an account or a potential also?
c) Once the lead is converted, I can no longer edit the contact in the Leads form. Do I edit it under potentials?
d) Where can I find a list of all my leads and where they are at in the funnel?

Thanks for the help. I apologize if these questions sound to entry level. I am still a beginner at this.