Basically, what this program does is that it copies your targets MAC address, channel number, essid and use it to create fake access point (Evil twin attack). Also it captures 4-way handshake, which will you use to get the password with phishing page you automatically made.
In final steps of this tutorial, Linset will automatically create your evil twin, and it will start DOS attack on the REAL(original) access point, so that all the clients which were connected will be DISCONNECTED, and automatically redirected to your fake AP (If signal is strong enough).
After they successfully connected to your trap, they will get phishing page to repeat their WPA/WPA2 password, and when they do that, you are DONE!
Enjoy.