You can create a new property from the Assemble Properties page.
First decide whether to create a new property at the account level or at the project level. The account level and project level instructions for accessing the Assemble Properties page differ from one another. It's important that you select the correct level before you create a property.
Follow the steps in Manage Assemble Properties to select whether to create a property at the account level or the project level.
Select Create Property from the list on the right of the Assemble Properties page.

The Create Assemble Property dialog box appears.
Complete the following:
Click Save & Create New or Save.