Not sure if he posted settings anywhere. Engraving is generally pretty forgiving and how you want to do it might depend a bit on the level of detail in your image. It might be faster and get you better results if you can do a test, but if this is your only sample of acacia, I might see if @shop wants to share.
Bought some nice marble/Acacia half and half coaters from Target for a request for 2 sets for someones housewarming gifts. This was my first engrave on this wood and this companies coasters. Unmasked I used settings: 100 - 65 - 340lpi with auto focus: unmasked: GF Pro. I noticed at 70 power, I could see more resin around the engrave, at 65 I did not get this. They engraved just perfectly! Thank you for all your input, it greatly helped.
What exactly does “all I get are burns” mean? All engravings are burns. The first thing that came to mind, though, is that if you place a cutting board on the floor of the machine without raising it up into the focal range of the machine (~1.5-2" off the floor), your engravings won’t look very good because they’re entirely out of focus. Read through this post for how to engrave on thick objects correctly:
Ditto what @dan84 said, and also I might suggest posting a photo of your results, and a screenshot of what you’ve got in your machine (showing the commands on the left all the way to the name of your machine on the right) - it’ll give us a better idea of where it’s messing up