You must have an isolated shape layer in your file (use Photoshop's shape tool). After you log in, click "Add new variable". Then click "Select the correspondent layer" in the drop-down menu. Fill in the requirements concerning this variable (variable name and optional/required variable) and click "Save".
You must have an isolated shape layer in your file (use After Effects' shape tool). To add color to a shape variable, you need to enable the shape layer by going to "Layer Style" > "Color Overlay".
Go to the Variables tab in plugin/script, select the shape layer from the drop-down menu, set its name, and click "Add Variable".