With the power ON, press once the "Record" button which will start the recording. The blue LED lights will be blinking while in record mode. The lights can been seen in your peripheral vision while wearing the glasses.
For those iSee sunglasses camera that has a camera icon (Rev2), you may follow the instructional video from the link below:
https://www.youtube.com/watch?v=7nJMHdzZS7M&list=UUsfbLh7Rw-ZmL0iSmtLBmIA