We have two Applications for our users - one is the older Portal type applicatio

Are you referring to the list in the Design Page, or the Applications Portal Link on tempo? Also, how does the behavior of the Portal based application differ from the Tempo based application?

Am referring to the Applications drop down just to the right of the User's name on the Tempo page. The applications happen to be similar the Tempo app is replacing the Portal app eventually although for now both apps are available to users. The Tempo app has no "portal" page.

What we'll be doing in these cases is replacing the portal start process channel with a rich text display area that contains directions to utilize the Tempo app. Since the application can no longer be cleanly launched in portal once converted, this area will be used as a text area for user training instead.

Is that something that I as the app developer can do?

This sounds like the Application Link to Portal: forum.appian.com/.../Post-Install_Configurations.html

Clicking on the list of applications from this will only send to users to the Application's Portal page. Since this application was not build with Portal in mind, the page is likely to be blank. It is possible to create a custom page for the application and information about the Application portal can be found here: forum.appian.com/.../Application_Portal.html

Also checkout this document on converting portal user interefaces to tempo bes practices: forum.appian.com/.../Converting_Portal_User_Interfaces_to_Tempo_Best_Practices.html

I created a custom page but there does not appear to be any way to make it the "Portal" page for my Tempo Application

You will have to configure this page as a navigation item in the old /designer portal interface. I'm sure you noticed there is no way to navigate directly to the 'navigation' items for a process model that does not currently have any portal navigation set, but you can do so by plugging in your environment url and application ID in the link below. Note, the application ID can be obtained by exporting the application and reviewing the export log.

https://<YOUR_SITE_URL>/suite/applications/launchApplicationBuilder.popup?appian_environment=designer&action=view&appId=<APPLICATION_id>&locale=en_US

Once you are in there, you can configure the page as a navigation item, assuming it has been added to the application bundle. The first page configured should load as the default then, when users choose the app from the portal dropdown. Let me know if that helps.

That worked great - thank you for the tip