Here's a quick tutorial of how to setup your computer for multiple monitors.
Right click anywhere on the desktop and select "Display Settings". This will bring up this screen:
On this screen you can change the orientation of your screens by dragging them around to the correct positions.
You also can change whether screens are a duplication or extension of each other, the amount of zoom each screen has, and which one is your primary screen as you scroll down:
Whichever screen you use on your smart board should be your main display if you want to use the onscreen keyboard. If you've turned on your computer but can't find your logon screen, you can power on the projector/smart TV.
Smart Board Appearing Without Touch Screen
Windows 10 has deprecated the feature of using touchscreen on any screen other than a main primary monitor. If you can see the smart board screen connect, there are a few options to get touch screen working.
Go to Settings > System > Display like in images above
Option 1 Change Main Display: You can select "Identify" to see which screen is which. When you know which screen is which, select the smart board monitor. Scroll down under "Multiple Displays" and checkmark "Make this my main display." This will make touch screen active on the smart board and keep the monitor and touch screen as multiple displays.
Option 2 Duplicate Screen: You can select "Identify" to identify screens and verify which monitor is NOT your smart board. Select your main screen and scroll down to "Multiple Displays" and select "Duplicate These Displays" in the drop down menu. This will make both your monitor and the smart board the same image and give touch screen.