I am trying to earn badges. How do I complete the stack Overflow survey?
Stack Overflow's Developer survey is generally conducted every year in the month of January-February and results are announced somewhere between April and May. As Mark Kirby stated, you just missed it this year.
Whenever a new is available, you'll see survey's announcement in the yellow box on the right side under "The Overflow Blog". Currently, these are the hot topics on "The Overflow Blog".
Alternatively, you can keep on eye on survey questions on Stack Overflow Meta or The Overflow Blog or change email settings as noted by Mark. But again, the company would decide when the surveys would happen.
If you're eager to earn more and more badges, please visit badges page in help center to know the secrets to earn them quickly. Also, please note, the badges are non-transferrable, i.e., Ask Ubuntu's badge won't be reflected on other sites on Stack Exchange network such as Stack Overflow or Super User. Meta badges are also independent of the badges on the main site.