If your keyboard has brightness controls, press Option–Brightness Up or Option–Brightness Down.Then double-click System Preferences, then click Displays.
At least 1080p video over HDMI, and some Mac models support higher resolutions when connecting to 4K displays, 5K displays, and Ultra HD TVs.
Mac computers that have an HDMI port comply with HDMI 1.4b and support:
Learn how to identify the ports on your Mac. Mac computers that have any of the following ports can connect to HDMI devices. Use the standard USB port to connect devices such as your flash drive or camera or a USB cable for syncing and charging your iOS devices.
How toinstall a auvio usb hdmi pc to tv adapter? This particular device identified in the link has the power from the USB of the laptop to operate, the sound from the audio out of the laptop, and assuming you have a VGA out for a monitor the connection to the converter will give you choice of resolution.