Security for your wireless network is a must and you set it up, or find out the existing setup, by typing that address - 192.168.2.1 - into the URL bar of your browser, preferably Internet Explorer.
That opens up the router's settings pages at a login page. The manual that came with it tells you the access details, usually admin and password in that order but check that first. When you get in, you can see the nettwork name, known as the SSID.
Find the wireless section and then security. Go for the highest level, called WPA2 and enter the number of characters it tells you to, keeping a note of it ofor yourself. Save the changes and logout then use that informaiton you noted to tell your computers how to connect securely to your SSID.