Figure it out by jerkin with key commands:
- CMD+SHIFT+G to Go to Folder
- Enter "/Applications"
- Arrow keys down to "System Preferences"
- CMD+O to open
- Type "Bluetooth" into the search field (default active field in System Preferences)
- Press "Enter" to open the Bluetooth preferences
- CMD+N to setup new device
- Arrow keys to select the mouse
- Press Enter on the selected mouse
For any future people looking at this, you can simplify this process using Spotligh:
- CMD + Spacebar (opens Spotlight - Mac's search feature)
- Type "Bluetooth" - use arrow keys to select Bluetooth with the heading system preferences (most likely the 2nd or 3rd option)
- Continue from CMD + N as above
This cuts out about the first half - additionally, using the keyboard to automatically open up spotlight and search for a program/file is often way faster than navigating to find it in everyday life too!
(Another really useful command: CMD+W - close window or if browsing the internet close tab)