We’re launching a new user interface in the coming months. Read all about it in this article and then ask questions or comment below.
Thanks for your questions.
There's no app to download. You'll be able to access Channeltivity directly via your mobile browser.
In the new UI, Internal Users with Widget Content Administration permissions will be able to manage Articles and Welcome Messages. Changing the layout of a page or adding/removing Widgets will require Administrator permissions. To answer your question specifically: Yes, you can give Internal (not Partner) Users access to create and edit Articles by making them a member of a Group with Widget Content Administration permissions.