Here are the steps for pairing a Bluetooth device to a Chromebook.
Click on the 3 dots on the top right of the Chrome Browser, then open Settings.
2. Click on Chrome OS settings. That will bring up the window shown bellow.
3. Click on the arrow to the right of Bluetooth to expand that section.
4. Turn on the Bluetooth or press the Bluetooth pair button on the device. Wait a couple seconds. You should see the name of the device appear under Unpaired devices.
5. Click Pair Device.
Note: There may be more setup needed depending on the device: for instance, if it is a speaker you may need to go to audio settings and select the speaker.