Using two monitors

Ive been looking through the forums and settings and dont see a way to set it to extend.  Is there an easy way to do this?  Or do I have to just pull the screen over the two extended screens?

One of the ways I have it set up for two monitors is using the HDMI out on my laptop into my tv and extend my desktop with the display settings on the desktop screen. Then as I am logged into the DM side of things right click on the join as player button and open in a new tab or window then drag that tab/window over the the extended monitor. I have not messed with any of the screen casting apps and devices maybe they can cast just the window you want to a tv or monitor. 

Thanks for the reply...   Ive been doing more searching and found that you can pop out the chat bar so Ill do that along with the Character Sheet Ill have plenty of room for the map.