You can import custom entities by using a JSON file.
Before You Begin
Download the import_entity_manager_template.json file, and then update the template file with the values that are needed to create the custom entity. For information about the JSON name/value pairs in the template file, see JSON Name/Value Pairs.
From the navigation pane, go to Activate.
The Activate page appears.
Under Settings, click the Entity Manager tile.
The Entity manager page appears.
In the upper-right corner of the page, from the Add entity list, select Import entity.
The Choose File to Upload dialog box appears.
Select the JSON file that contains the custom entity that you want to import.
The custom entity is imported and appears in the section to the right of Entity list.