To control the servo and NeoPixels in CircusPython from a client computer (phone or tablet), you use the Adafruit Bluefruit LE Connect App. Install it from the Apple App Store or Google Play App Store.
Start the main program running on your CircusPython project. Then start up the Bluefruit LE Connect app, and make sure it's in Central Mode (left button on the bottom). When you start the app, you should see a device named CIRCU or CIRCUITPY. If there's a long list of devices, you can shorten it by turning on the "Must have UART Service" switch.
To connect to CircusPython, touch the Connect button. You should see "Connecting" and then "Discovering Services".
If you don't see CIRCU or CIRCUITPY right away, try pulling down to refresh. If that doesn't work, try turning Bluetooth off and back on on your phone or tablet and restarting the app.
After you connect, you'll see a menu of how you can interact with the device. Choose Controller.
After you choose Controller, you'll see another screen with more choices. Control Pad and Color Picker are used for this project.
Here's the Control Pad screen. Use the Up and Down buttons to move the servo arm up and down and make Blinka jump through the NeoPixel ring.
To change the color of the NeoPixels, use the Color Picker screen. Choose a color and press Send Selected Color.
That's it! This simple project is only a jumping-off point. Add more servos or other things, and use the other buttons (see the codes for the other buttons) to control them.