What’s included
To use your Mac Pro, you need two accessories included in the box—the Magic Keyboard with Touch ID and Numeric Keypad and either the Magic Mouse or Magic Trackpad.
Important: To begin using your Magic Keyboard with Touch ID and Numeric Keypad and Magic Mouse or Magic Trackpad, make sure the on/off switch of each device is on 
Magic Keyboard with Touch ID and Numeric Keypad: Your rechargeable Magic Keyboard with Touch ID and Numeric Keypad is already paired 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 Charge Cable.
To customize how your keyboard works, go to System Settings, click Keyboard in the sidebar, then choose the settings on the right for keyboard, text, shortcuts, and input sources. To learn what the function keys on the keyboard do, see Magic Keyboard with Touch ID and Numeric Keypad.
Magic Mouse: Like the Magic Keyboard with Touch ID and Numeric Keypad, your rechargeable Magic Mouse is already paired 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 Charge Cable.
To customize your gestures, go to System Settings, then click Mouse in the sidebar to see all the scrolling, clicking, swiping, and tapping options.
Magic Trackpad: If you configured your Mac Pro with the Magic Trackpad, it comes paired 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 Charge Cable.
To customize your gestures, go to System Settings, then click Trackpad in the sidebar to see all the Point & Click, Scroll & Zoom, and More Gestures options.
If you purchased a Magic Mouse or Magic Trackpad separately, connect it to your Mac Pro with the included USB-C Charge 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.