Transformation is when a figure move from one location to another without changing its size and shape. The figures much be Congruent. There are 3 tabs of Transformation and they are Reflection, Rotation and Translation.
Congruent figure are the same size and shape they dont change. The second figure is the first figure copy. Their location are also the same.
Reflection is when a figure has a copy it self but is opposite. When you look in a mirror you see yourself but it looks weird because the image is looking back at you. Reflection figure are always Congruent.
Rotation figure must be Congruent except that the figure change it's location.
Rotation figure go around a point. They stay Congruent but they change their location.
Translation and Reflection are kind of the same but Translation figure are the second figure of a Translation the exact copy of the first nothing change. Translation figure at Congruent they don't change their location, size and shape.