Q: how do I set my I Mac to watch HDMI movies on my sharp hdtv

Hello Fixer76,

The resources below will explain how to connect your Mac to a TV using the thunderbolt port and an adapter for the HDMI.  I'll also include some information about Apple TV, which allows you to do this wirelessly.

OS X Yosemite: Use your TV as a display
https://support.apple.com/kb/PH19036?locale=en_US​

About Mini DisplayPort to HDMI adapters - Apple Support
https://support.apple.com/en-us/HT202079​

OS X Yosemite: Connect multiple displays to your Mac
https://support.apple.com/kb/PH19039?locale=en_US&viewlocale=en_US​

Set up the displays as an extended desktop

You can arrange your displays in any configuration to create an extended desktop. For example, you can set your displays side by side to create one large continuous desktop. 

1. Choose Apple menu > System Preferences, click Displays, then click Arrangement.

2. Follow the onscreen instructions.

Set up the displays for video mirroring

Video mirroring shows the entire desktop on each connected display.

1. Choose Apple menu > System Preferences, click Displays, then click Display.

2. Set both displays to the same resolution.

3. Click Arrangement, then select Mirror Displays.

Apple - Apple TV - Play your favorite HD content on your HDTV.
https://www.apple.com/appletv/what-is/​

Take care,