If you've never used the goggles before, you should start out with the tutorial or the Parable of The Hackasaurus.
Here's the bookmarklet: X-Ray Goggles.
Note that if you're on a mobile browser, you may need to manually create a bookmark to the following URL:
Once the goggles are activated, you can press H for help.
If the goggles don't seem to be working, try running the test suite. Then report a bug and be sure to mention whether the test suite failed.