I want to add another App to my customization. Do I have to sign up from the Orange Apps site, or can I just add it on to my account?

From the main Orange Apps dashboard, click on your name in the top right corner, then click on Account. If you are a current Lead Small or Parent Cue Orange Apps customer and want to add the other resource, select Subscription from the sidebar. From there, you can manage your current subscription plan or add to it.