Integrate expected results of each action

[felixpou]

In order to accompany the self-served tutee, it would be useful to inform of expected results inline with the exercice instructions.

For each step, immediately follow the instruction with a description of the expected result. This can be:

• A Visual Cue: "You should now see a new file named index.html in your folder."
• A Description of a Change: "The square's position value should change to 500 on the properties panel."
• A Screenshot or Image: Show a picture of what the screen should look like after the step is completed. This is especially helpful for visual tasks.
• A Confirmation Message: "you will see the message 'Installation complete' in your terminal."

And provide explanation of what is seen where it is not self explanatory.