Blender how to move a point across Axis Lock

Let say you want to move a point in your game object only along X, Y or Z

this is how you do it

1. First, select the point by right clicking it
2. PRESS "G" to grab
3. PRESS "X" then you can move it along x axis, PRESS "Y" then you move it along y axis, and PRESS "Z" then you can move it along z axis

hope that help