The music controls do not come up at top of screen. Have to swipe homepage to another screen to get them, but isn't my ipad open then? Best way for me was to play music and then turn off power button. Got black screen and music kept playing, but can't follow about turning them on or off with double tap
If you can swipe a home page, then the iPad is not locked. If the iPad is not locked, you can't get the play controls on the lock screen. The whole purpose of the music controls on the lock screen is to give you some control over your music without having to unlock the device and go to the music app.
If you want to control the music without opening the app while the device is unlocked, double tap, then swipe the task bar to the right. You'll see music controls, brightness, and a mute or rotation lock control.
The double tap on the home button (the one on the front face of the device) only works if the device is locked (with a blank screen) or you are on the lock screen. The one that has the slide to unlock control.
Check Settings > General > Auto-Lock. The iPad automatically blanks the screen and locks after the elapsed time if there has been no other imput. If you have it set to Never, the only way to lock the screen is to push the Power Button (the one on the top edge, same side as the headphone jack). This will put the iPad to sleep (blank the screen). The next time you push the Home Button you'll be on the lock screen.
Note, the Smart Cover or Smart Case will not lock a device with Auto-Lock set to never. It just turns off the screen.
This is the Lock Screen. Notice the 'slide to unlock' control a the bottom.
This is the screen you get when you double press the Home Button when the iPad is locked. Notice the play controls at the top have replaced the clock display.
BTW, when I say double press the Home Button, I don't mean leisurely. This is two quick presses, the same as you'd do on a computer when double clicking with a mouse.