This video explains some of the academic research performed in the ACM CCS 2017 paper "Key Reinstallation Attacks: Forcing Nonce Reuse in WPA2". It's not a guide or tutorial on how to hack people. Instead, the video was made to make people aware of potential risks, and to motivate everyone to update their smartphone and laptop. By updating your devices you (normally) avoid the risks mentioned in the video! For additional information visit https://www.krackattacks.com

Note that devices different from Android and Linux are less affected by the attack. That's because only Android and Linux (re)install an all-zero encryption key.