The research study and usability survey may takes place at Googleplex in Mountain View, California, or other Google office around the world. Other form of studies include remote usability study from a high speed Internet enabled computer and phone, visit by a Google researcher in field study, or simply fill out an online survey. Payment differs by type of studies and survey methods, but generally pay $75 for each hour that is spent with a Google researcher, either in person or on the phone.
To participate in the Google survey, first you need to sign up and register in Google User Experience Research program, and wait for Google to screen and invite you to the study. Good luck.