1. Open the "Zentangle Coloring Book" app on your mobile device.

2. On the main screen, browse through the collection of owl-themed Zentangle drawings and select the one you want to color.

3. Tap the drawing to open it. You will see a black-and-white image composed of intricate, repeating patterns.

4. A palette of colors will appear at the bottom of your screen. Scroll through the palette and tap on the color you wish to use.

5. Touch the area of the drawing you want to fill with the selected color. The section will instantly be filled in.

6. Continue selecting colors and tapping on different pattern areas to complete your design.

7. If you want to change a color, simply select a new one from the palette and tap the desired area again.

8. Use the zoom feature by pinching the screen to color small or detailed sections more accurately.

9. When you finish your Zentangle artwork, tap the camera or share icon to take a screenshot.

10. Share your colorful creation with friends or save it to your gallery to admire later.