Was looking today for a way to test mobile workspaces in Dynamics 365 for Operations (still no good abreviation). This is a bit hidden.
To be able to create a mobile workspace you log into D365O. Once you have logged in you, goto the address bar in your browser and add &mode=mobile to the end of the address and press enter.
Go to the module where you want to create the mobile workspace and click the settings wheel in the top right corner and a new menu item is visible
Click mobile App menu item and then click + Add
In my example I am in the Project module. I click Add to create a mobile app
I click + Add Page and give it a name and a description and click Done
Click + Select Fields to add which fields to view. You add fields by clicking on the plus on each column and click Done when you are ready.
Click Done and Publish workspace to finish the Mobile Workspace.
To test your Mobile workspace, install the Microsoft Dynamics 365 app from Google Play Store eller från Apple App Store, add the URL to your Dynamics 365 for Operations tenant, log on with your Azure Active Directory account and test your workspace