You are able to create a seating plan with a mixture of both reserved and unreserved seating sections within your account. When creating or modifying your seating plan, sections that have seat numbers allocated will be allocated/reserved seating. It is useful to name this section (for example) 'Front Stalls - Reserved' as this description along with the seat numbers will display on the customer's tickets.
For a section to be offered as general admission, simply add the seats to the section without any seat numbers and row letters. A customer will be able to book this section but will not be offered the option to select specific seats. It is useful to name this section (for example) 'Rear Stalls - Unreserved' as this will also be displayed on the customer's tickets.
When booking online, customers will be asked to select their seats within a reserved seating section, but will bypass this screen if they select the unreserved seating section.