Hi @OzPingouin,
A good place to start is here. It’s the topic which memrisesteph linked to previously.  It may look a bit daunting at first but I, too, had no previous experience of scripts and there are only a couple of steps to go through.  If I can do it, anyone can!   I can now switch the script on and off depending on whether I am doing a typing course that contains phrases (more than 15 characters) or a non-typing course.
  I can now switch the script on and off depending on whether I am doing a typing course that contains phrases (more than 15 characters) or a non-typing course.
To get started, click on the “Readme” link in cooljingle’s first post in that other topic and then install the relevant extension. I use Chrome so, for me, it was Tampermonkey. When that’s done, you should see a new button on the top right hand side of your toolbar. For Tampermonkey, it’s a black square with two white dots.
Next, go back to the “Memrise All Typing” instructions and install the script by clicking on the link provided. You’re nearly done! 
Next, click on the new toolbar button and then choose “Dashboard”. You should see that the “Memrise All Typing” script has been added. It should say “Version 0.1.4”.
Yay!  You’ve done it!  
To turn the script on or off when you are learning/reviewing on Memrise, click on the toolbar button and then on “Enabled”. If the green tick is showing, it will be set to ‘all typing’. If the red cross is showing, the script is turned off.
Good luck!  
 
 I know the basic concept of les and des: but I don’t know how to apply it here, i.e. why is “les” used in one instance and “des” in the other, while the English remains the same. Are both versions valid in French (and then they just made a mistake in the organization of the course), is one wrong, i.e. French people wouldn’t put it that way (and they made an actual grammar mistake in the course), or is there a rule that explains why to use “les” with colour and “des” with the size of the eyes?
 I know the basic concept of les and des: but I don’t know how to apply it here, i.e. why is “les” used in one instance and “des” in the other, while the English remains the same. Are both versions valid in French (and then they just made a mistake in the organization of the course), is one wrong, i.e. French people wouldn’t put it that way (and they made an actual grammar mistake in the course), or is there a rule that explains why to use “les” with colour and “des” with the size of the eyes?