Created new developer org, but not understanding how to enable lightning experience.?

Please help!  I am stuck on creating flows.  Can't seem to work.  I keep on re-doing my work and not sure if I am doing it right.  The challlenge as follows:

To pass this challenge you will need to create a flow that implements the business process of Account, Contact, and Opportunity data entry and place it on a Visualforce page.The Flow will need to be called 'New Customer Flow'.
The Flow should have a screen with fields for First Name, Last Name, Company Name, Opportunity Amount, and Opportunity Stage.
The Flow needs to have steps to create an account, a contact, and an opportunity from the data entered.
Opportunity name, close date and stage are required fields. Name the Opportunity '{Company Name} - {Last Name}', set the close date to one month from today and set the stage to 'Prospecting'.
The Flow should be invoked from a Visualforce page.
The Visualforce page should be called FlowPage.
The Visualforce page will need a component to reference the 'New Customer Flow' process.

If possible, if you can provide a snapshot.

Thank you.