The peanut-butter sandwich recipe
Tell a robot to make a sandwich and order matters: bread first, then peanut butter, then jam — swap the steps and you get a mess. A program is a recipe run in exact sequence, and a loop is saying 'spread ten times' without writing it ten times.
Step by step
A program is a list of steps the computer follows in order, top to bottom. If you swap the steps, you get a different result!
Loops repeat
A loop block runs the steps inside it again and again, so you don't have to copy them.