How choose a plane and draw a sketch on it?

I realized:
1. select the plane that you want by clicking.
2. right click on the selected plane and choose the((3D sketch on plane)) button.
3. now you can draw any sketch on that plane.

why 3d sketch? Can't you use normal 2d sketch?

Edit: i created a new plane and then, clicking right button, select sketch

tried to select it?

planes you create works like original planes....so if you can draw a sketch on Front Plane (for example) you can draw a sketch in other planes