explain the principles for safe moving and handling

Hey everyone!
I need your help with something really important. My younger son is studying at the University of Manchester and he's doing this project on carpentry, which involves a lot of moving and handling heavy stuff. Now, he's asked me to explain the principles for safe moving and handling, and I'm kind of stuck! I want to make sure I give him the best advice possible, but I'm not quite sure how to put it in simple words that he'll understand. Can you help me break it down? I want to make sure he knows how to lift things properly without hurting himself, and how to use tools safely too. It's really crucial for his project and for his own safety! So, if you have any tips or if you know of any resources that explain this stuff in an easy-to-understand way, please share them with me! I'd really appreciate it, and I'm sure my son will too. Let's make sure he's got all the knowledge he needs to stay safe while he's working on his carpentry project.
Thank you