Switch to the single view first. click on the video image.
At the image bottom, it should popup the control menu. Choose PTZ icon.
Other Useful Tips:
1. Drag the image to adjust PTZ View direction.
2. Click on the image to focus automatically.
3. Scroll up/down to Zoom in/out.
4. Click the lower-right corner icon to set the Preset. 
(see the Red Arrow; Preset button)