1. Sliding, reflecting and rotating congruent shapes
You could start by asking the pupils what they understand by these words. You may well want to change them into equivalent words they’re more comfortable with.

2. This shows the outline of two identical shapes which have been put together without overlapping. Can you see where the boundary line must be? How would you describe how one shape is transformed to the other shape?
[One possibility: Rotate lower L shape 90 degrees anticlockwise about (1,2)] See GeoGebra file.]

3. The same idea
[One possibility: slide lower shape up two units] See GeoGebra file.

4. The same idea again. [One possibility: Flip one shape about the diagonal line through (0,0) and (3,3)]
Hand out the next sheet and ask the students to find the boundary line for each shape and then clearly describe how to transform one shape onto the other. Any descriptions need to be perfectly clear so that if they read them out, you (the teacher) would be able to follow their instructions exactly without needing to refer to their diagram.