The Maxon App is your hub for accessing products like Zbrush, Cinema4D and Red Giant. The app also lets you manage the licences and get updates for these products.
On the left hand side you’ll see three options, Products, Updates and Licences.
To read more about Installing and updating your products see this article.
To read more about moving your licences see this article.
In the top right you’ll see your email with a cog, this is where you can sign out, access account settings and get support.