STEP 1: Open Google Chrome

Open

STEP 2: Select Menu (3 Stacked dots) in the top-right corner, then select Cast.

Open

STEP 3: From the Cast box, select Sources then Cast Desktop.

STEP 4: Select your Chromecast from the list. Your Chromecast will be named [Room Number]cc.

STEP 5: You’ll be asked what you’d like to share. Your Entire Screen is selected by default. Make sure Share audio is checked, then select Share.

STEP 6: A blue Casting icon will appear on your Chrome toolbar to indicate you are casting.

Don’t close the Chrome window you’re using, it will stop casting. You can minimize Chrome if the window is in the way.

To Stop Casting

Step 1: Select the Cast icon on top of Chrome.

Step 2: Select your Chromecast to stop casting.

Source: https://www.techsolutions.support.com/how-to/how-to-cast-the-windows-desktop-to-chromecast-12539