Hold the paddle with a shoulder width grip.
Most of the power should come from your hips and core.  
You are leaning into the stroke.  
Reach out and submerge the blade into the water.
 Lean into it with your hips and core. 
Your 'top' arm will remain straight and push
Your 'bottom' arm will bend and pull.  
​Use your legs too.  A slight bend in the knees will help with it.

When you stroke on the right side of the board, you go left.
When  you stroke on the left side of the board, you go right.
When you stroke front to back, you go forward.
When you stroke from back to front, you go backward.