Improve video tutorial

[Era-Dorta]

• Stress that the annotator should leave the key pressed when the person talks and do an actual example
• Stress that the participant not found is a very rare case and they should really look hard for them
• Say that the tutorial is an overview but please make sure to read the instructions
• Be very clear about each step, so say "Step 1" and point with the mouse pointer, then explain, then say "Step 2", etc