the cut button makes what you need here : simply select you project(s) / folder(s) (to select several at once use Ctrl + clic) press cut, then go to the the folder you want to move your items to and then press paste. Let me know if my explanations are clear enough !

It works, mathieub! Thank you! By the way, I just checked out your profile and you're really good at your renderings! Keep up the good work!

Thanks, but for renderings you really should check zanna's profile, https://www.mecabricks.com/en/user/zanna/renderings and renderbricks's : https://www.mecabricks.com/en/user/Renderbricks/renderings

Your welcome! I've seen both of those people's renderings. They are both certainly spectacular at it.