D-Link DIR-300 User Manual page 68

Section  - Changing the Computer Name and Joining a Workgroup
3. Click the Computer Name tab in the System Properties window and
enter a description of your computer in the textbox. When you are finished,
click the Change button.
4. Go to the Computer Name/Domain Changes window and
click the radio button next to the Workgroup you want to join.
When you are finished, click the OK button.
D-Link DIR-300 User Manual 68