1. In your browser, clear it so nothing is there and type 192.168.1.1 click go or whatever it says.
2. When you get to where you put in WPA, there should be a drop down arrow to choose WPA or whatever you want.
3. Then you have to type in a security password or it may say WPA shared key. Here is a site that you can use for that. I use it all the time.grc.com passwords
4. After that click save.
I have Linksys router and I'm guessing it is probably the same. I think this is what you want, not sure.