Refer to Google's support for basic internet troubleshooting.

Wifi Card

The WiFi card is often, but not always, embedded directly onto the Chromebook's motherboard.

Antennae

The WiFi card has two small ports for the anntenae that route up into the back cover and behind the LCD and bezel. These anntenae have two small connectors on each wire, they snap onto the ports on the WiFi card.These are usually pretty robust but in the case of a broken or missing port you may be out of luck with a repair.

Troubleshooting

When trying to log in or enroll a device, if you log into wifi and it keeps spinning and says "No internet connection", try a different wifi source. I've found some issues with test wifi sometimes. Also, a Power + Refresh might also do the trick. This also makes me wonder if im just not waiting long enough.

If you are having a hard time setting the Wifi cables into the port on the WiFi card, try using your plastic pencil tool. The flat side of the pencil is useful for pressing down the little metal connectors.