Click on the App section in the left menu.
If your plan does include Apps, you will get a notification:
You can upgrade your plan to gain access to the Blitapp Apps.
Click on the Add new App button to add a new App.
Then, click on the Add new App button.
This brings up a new form to create your App. First, choose the Type of App you want to make. If your plan includes a limited number of Apps, you may have a restricted list of App types available.
You can check how these Apps work and how to configure them:
Once an App has been created, it must be added to one or multiple captures to be used. You can use the Bulk Edit feature to add your new App to multiple captures at once.
See also: Configure an App, Blitapp API, Bulk Edit