This lesson is going to let you make a flag wave in the wind.
Go to the website http://en.wikipedia.org/wiki/Gallery_of_sovereign-state_flags to find the flag of the country you want to make wave.
Click the flag you want. This gives you a bigger picture of the flag.
Right click on the flag and click "Save Picture as."
Save the picture.
Start Blender.
Delete the cube.
Go to front view. 
Add a plane.
Go to Side View. 
Press the R Key and rotate the plane 90 degrees.
You will need to resize the plane. The size of your plane should be about the same size as the flag.
Press the A Key to deselect all vertices. They should
be pink when deselected. 
Use the B Key and select the two right vertices.
Use your arrow keys to drag the vertices right or left.
Go back to front view.
Press the F5 key for shading.
Click Add New.
Press F6 for texture buttons.
Click Add New again.
Add a texture type of Image.
Click Load.
Using these buttons navigate to your file.
Click your flag.
Click Select Image.
Press F9 to go back to the editing buttons.
Add a modifier called Wave.
Go into Edit Mode using the Tab Key.
Make sure all your vertices are selected. Vertices
should be yellow.
Press the W Key.
Click Subdivide.
Subdivide 3 or 4 more times until your plane looks like
this. 
Go to Object Mode.
Look at your flag.
Click Set Smooth to smooth out your flag.
Use your arrow keys to watch your animation.
Look back at all your wave options.
Click on the Y axis to run the wave off on the Y Axis.
Use your arrow keys to run the animation. Your arrow keys are on the keyboard.