I would highly recommend securing your wireless network.
Wireless connections require security configuration to prevent anyone with a WiFi in range of your router from connecting to your network. They could do malicious deeds, such as hack into your network, or just leech off of your Internet bandwidth.
There are also unscrupulous hackers that look for open WiFi networks that they can exploit. They may hack into your files or use your Internet connection for illegal activities.
For these reasons most people set up wireless security on their wireless router requiring a password to connect.
ROUTER CONFIGURATION::
Download the manual if you don't have one. You'll have to do a Internet search for your specific model and include the terms "manual" or "setup" in your search.
Connect a PC or laptop via Ethernet to one of the router's LAN ports and follow the instructions in the manual to set it up.
If you currently have an open system, it is likely still configured to the ASUS factory defaults. The ASUS Default IP is usually http://192.168.1.1 and the username is "admin" and the password is "admin".
If the default has been changed and you don't know the login password you'll have to reset the router to factory default state. The instructions will be in the manual.
If the router is reset to factory default, thus erasing all user modified settings then it will revert to the default passwords. Be sure to change the password of the administrative interface of your router from the factory default for security.
Wireless setup is not too difficult, Just follow the instructions in the router manual or wizard set up program. If you're having problems either pay someone to set it up for you or find a knowledgeable friend to configure it. Once the wireless network settings are configured it's a fairly trouble-free system.
Good Luck