Once you have logged in to your DDBv1 Account you will have a list of all screens on your account.
To update the tenant list of a screen, you need to click on the screen name to bring up the editing page.
Update a tenant by editing the details in the relevant textbox.
Add a tenant by filling in the details in the empty bottom row (see 1). After you save the update, a new empty row will appear at the bottom of the list if you want to add another tenant.
Rearrange tenants by dragging and dropping the rows into different locations. This will only change the order of the tenants on the screen if the screen is not set to order by name or level.
Save your changes by using the Save button. This will not update the screen with your changes, but will leave the listing updated for you to come back to later.
Update the screen by using the Save & Deploy which will commit all your changes and update the screen to show the new tenant listing.