Click Insert-Shape on the navigation bar and select Ellipse. Then hold down shift and draw a right circle. Select the circle and click Animation-Custom Animation. Detailed steps:

1. Open PPT, click Insert-Shape on the navigation bar, and select ellipse, as shown in the following figure:

2. Then hold down shift and draw a right circle, as shown in the figure below:

3. Select a circle and click Animation-Custom Animation, as shown in the following figure:

4. Click Add Effect, as shown in the figure below:

5. Click on the "wheel", as shown in the figure below:

6. When playing the slide show, the rotating animation effect is completed, as shown in the following figure: