Download the app from the store and launch it. You will see an interface requesting information to start a new connection. You can use your computer's IP address to connect. If the mobile device is on the same network as your computer, it should appear on the list of available machines.
If you're trying to figure out how to get dual monitors to display during a remote session, you're out of luck. The display configuration cannot be edited during a remote session. The resolution is set and locked by your client device.
If you're remoting into the computer from a client with a keyboard, you can use the Ctrl, Alt, and Del keys on the keyboard. If this doesn't work or isn't an option, choose the keyboard icon from the top of the screen. Select Ctrl + Alt + Del in order.
You can restart a Windows 10 machine using Remote Desktop with a couple of methods. You can use the Start Menu to access the shutdown/restart options or use Ctrl + Alt + Del. There will be a power icon in the bottom-right corner with an option to restart.
While remoted into a Windows 10 machine with Remote Desktop, you can use all of the normal print functions. Any printers connected to the machine will appear as an available device. Select the printer you want to use and print away!
If you want to print something on the client-side that's stored on the remote computer, you will need to transfer the file to yourself. If you're remoted into the computer with the file, use any method you like to send it to your client device—email, cloud storage, etc. Once you have the file on your client device, you can print it locally.