If you don't see the the Silicon Connector for Box option in your Window > Extensions menu, there might be a problem with your Silicon Connector for Box installation.
- Try the steps described in this article.
- Clear your preferences while starting InDesign. To do that, hold down shift+ctrl+alt+cmd on Mac or shift+ctrl+alt on Windows, immediately after launching InDesign. This can be a little tricky to do in time but if you hold the keys down in time, you'll see a dialog asking if you want to clear your InDesign preferences. Choose Yes.