Before continuing, ensure your projector is turned on and has an Airtame by checking both HDMI sources. If it does, you'll see an Airtame screen with some info on it.

Steps:

On the Chromebook, browse to airtame.com/go 

2. Enter the pairing code that is shown on your Airtame panel:

3. At this point it should say you're connected on the Chromebook, click 'Share screen':

4. Click 'Share screen' and select the window or monitor you'd like to share:

4b: Choose the tab / window / screen you'd like to share: