Contracts are generated based on a template that can be found under Settings->Contract Templates. You can have multiple templates, but only one of them can be the default, which is used when a customer auto-books or you create a contract using Method 2 below.
There are two ways for you to create a contract as shown below. A customer can also create a contract when they attempt to autobook an event.
Generate a contract in 1.5 seconds
When viewing a lead, simply change the status to Contract, by clicking the white box underneath the word contract. This will immediately create a new contract using the default template (if no contract exists for that lead) and set the lead status to Contract.