To create a screenshot of whatever is displayed on the iPad screen:
- Hold the iPad in Landscape mode.
- Press and hold the Sleep/Wake/Power button (at the side-left of the device)
- Immediately press and release the Home button (middle-right just outside the screen). See the two red circles marked in the image below.
This creates a screenshot of the current display, and gets stored in the iPad Photos gallery (Photos > Albums > Camera Roll)
How to take a screenshot