You need to be on the ULTIMATE plan or the PRO plan with the "Unlimited boards" feature selected. The LITE plan allows you to have 3 lists maximum.
Parking lot and boards allow you to store tasks that don't have a particular date, they could be ideas, things to do later, or projects. Boards can be used to run Kanban projects, or store tasks in lists.
To access the Parking lot and boards, click on the week breadcrumb. You will find the list of boards on the right (here; Parking lot and "Done")
A board is simply a list of lists of tasks:
By clicking the "Add list" button, you can add a new list.
You also have the option to add a new board by clicking "Add board".
There is no option to delete boards at the moment.
Customer support service by UserEcho