This part is about Loading the software and quick look.
Giving you a % power will be impossible without knowing what power your tube is. Even then not all tubes have the same power characteristic. All I can say is you will need to experiment . Use a single test letter or number and do some trials. Start with power of about 15% and speed of 50mm/sec. Look at your result and you can make a decision if you want your engraving deeper or shallower. Deeper means more power for the same speed (or increase both) shallower means more speed or less power. You will probably find that you get smoke browning around your characters. If you only have a small number of items to engrave then stick masking tape onto the wood before you engrave it. When you peel it off the staining will come off also and you will be left with a clean crisp result.
your videos have been a life safer helping me set up my laser machine.