You can either select an existing page, or click the + sign to add a new page.
Once you have added or selected the page on which you wish to add the Header component, click on the + sign next to your page title.
You will be shown all the existing components available for your Beezer subscription plan. Select the Header component and click Add Header Component button at the bottom of the page.
Once you add the Header component to your app page, you can edit the settings and customise it as per your requirements. Please click here to know how to setup the Header component.
Please Publish your app once you have made the changes, so they get reflected on your mobile app successfully.