Here's how to save filters for metrics divided by device category (mobile, tablet, desktop) in Google Analytics. For a simpler, throw-away method have a look at Filtering for mobile and tablet data in Google Analytics.
OS\Browser - Desktop
- In the main navigation, select Customization
- Choose +New Custom Report
- Give a title and name(s) to the report and tab(s) as you please, for - example: OS\Browser - Desktop
- For Type, select Flat Table
- For Dimensions, select +add dimension and add Browser Version
- For Dimensions, select +add dimension and add Operating System Version
- For Metrics, select +add metric and add User > Pages / Session
- Under Filters select +add filter
- Under Users, select Device Category
- Choose Exact and enter desktop
- Click Save
Device\Resolution\OS - Mobile\Tablet
- Under the created filter, select Edit
- Choose +add report tab
- You could call this one Device\Resolution\OS, or whatever you wish
- For Type, select Flat Table
- For Dimensions, select +add dimension and add Mobile Device Model
- For Dimensions, select +add dimension and add Screen Resolution
- For Dimensions, select +add dimension and add Operating System Version
- For Metrics, select +add metric and add User > Pages / Session
- Under Filters, we see a copy of our existing Device Category filter
- Under Filters, change dropdown selection Exact to Regex
- Under Filters, change Device Category value from desktop to mobile|tablet
- Click Save
- Navigate to the newly created tab