Hi monicajaye36,
I see you are a new user here in Apple Support Communities - welcome! I hope we find you contributing often in the future.
You don't mention whether you have the 11 inch or 13 inch model of MacBook Air, but both support using an external display through the Thunderbolt port. See these specifications pages -
MacBook Air (11-inch, Early 2014) - Technical Specifications
MacBook Air (13-inch, Early 2014) - Technical Specifications
Specifically -
Thunderbolt digital video output
- Native Mini DisplayPort output
- DVI output using Mini DisplayPort to DVI Adapter (sold separately)
- VGA output using Mini DisplayPort to VGA Adapter (sold separately)
- Dual-link DVI output using Mini DisplayPort to Dual-Link DVI Adapter (sold separately)
- HDMI audio and video output using third-party Mini DisplayPort to HDMI Adapter (sold separately)
So if your display uses Mini DisplayPort for input, connect it directly to the Thunderbolt port. With DVI, VGA, Dual-link DVI, or HDMI displays you would need an adapter. You can find them here in the Apple Store online - mini displayport - Apple
Thanks for using Apple Support Communities.
Sincerely.