You can set a password to limit the users. Whenever users will try to connect your wifi, they have to enter a password. But to secure your account, you must be login with your d-link router account.
Step 1: Open your web browser and type "192.168.0.1". Press Enter. You will be redirected to your administrator login page.
Step 2: Now type admin in the user field and leave the password blank. But if you have customized your dlink login information, you may enter your personal user name and password also in both the options.
Step 3: Close the setup tab and click "Wireless Settings".
Step 4: From the wireless settings, select the security mode that you want to apply in your router.
Step 5: Click on Passphrase option and type passphrase. Press confirm button.
Step 6: Now press the save button to see the changes you have made in your d-link router.
Protecting yourself online begins with your wireless network security. Secure your D-Link router to guard against unauthorized access to your wireless network.
How do You Secure a DLink Wireless Network?