What’s included
To use your Mac Pro, you need two accessories included in the box—the Magic Keyboard with Numeric Keypad and either the Magic Mouse 2 or Magic Trackpad 2.
Important: To begin using your Magic Keyboard with Numeric Keypad and Magic Mouse 2 or Magic Trackpad 2, make sure the on/off switch of each device is on 
(green is visible). The devices connect to your Mac Pro automatically.
Magic Keyboard with Numeric Keypad: Your rechargeable Magic Keyboard with Numeric Keypad is already connected with your Mac Pro and is ready to use. When you need to charge the keyboard or if you need to connect it again, connect it to your Mac Pro using the included USB-C to Lightning Cable.
To customize how your keyboard works, in System Preferences, click Keyboard, then click the buttons at the top to see the options available for keyboard, text, shortcuts, and input sources. To learn what the function keys on the keyboard do, see Keyboard.
Magic Mouse 2: Like the Magic Keyboard with Numeric Keypad, your rechargeable Magic Mouse 2 is already connected with your Mac Pro out of the box; you can use it anywhere within range of your computer. When you need to charge the mouse or if you need to connect it again, connect it to your Mac Pro using the included USB-C to Lightning Cable.
To customize your gestures, in System Preferences, click Mouse, then click the buttons at the top to see all the scrolling, clicking, swiping, and tapping options.
Magic Trackpad 2: If you configured your Mac Pro with the optional Magic Trackpad 2, it comes connected with your Mac Pro and is ready to use out of the box; you can use it anywhere within range of your computer. When you need to charge the trackpad or if you need to connect it again, connect it to your Mac Pro using the included USB-C to Lightning Cable.
To customize your gestures, in System Preferences, click Trackpad, then click the buttons at the top to see all the Point & Click, Scroll & Zoom, and More Gestures options.
If you purchased a Magic Mouse 2 or Magic Trackpad 2 separately, connect it to your Mac Pro with the included USB-C to Lightning Cable to use Bluetooth. Use this same cable to charge your devices as necessary, then unplug them and use them in the location that works best for you.