If you are wondering how to use your Android as Wifi router, then you need tether Android. Here is a free Android WiFi tether app which lets you do so, provided your Android is rooted.
To start with, you need Android WiFi Tether, which actually stimulates and takes care of the whole process. Once you root your Android, you can use this app to tether your Android in one click.
Its free and you need not do any kind of settings on your computer. In fact, it is the best way to tether Android in one click. This Android app is a way to create a instant WiFi hotspot.
NOTE: Be careful while using this app to tether Android because it runs on rooted device.