So you got a new Nexus or another Android running Android +4.2 and there’s no “Applications” menu entry in the settings menu.
No worries.
Go to the “About phone” entry at the bottom of settings, then scroll all the way down to the “Build number” menu entry.
Tap on it SEVEN times. (You’ll see funny “toast” messages come along)
When you go back to the main “Settings” menu, you will see a “{ } Developer options” entry.
Cheers