After an answer today; to my crie de coeur by Wayne, I was able to download and read what I needed to see. I have attached a picture showing about 25% of my first handmade toy. Should be obvious what they are at any rate.
I used 40mm cubes of pine (nice endgrain) and I created the letters in Affinity Designer and exported them as .svg files. Herein was my first issue. The .svg files were not readable by Snapmaker JS or Luban. The rationale behind using vector files is so that one can make the file any size because it is resolution independent. I was also having difficulty finding the actual workspace in Luban and Wayne helped me with that.
After discovering that the integrity of the .svg files was in doubt as far Snapmaker software was concerned, I made the .svg files fit into a 39mm square and converted them to .jpg files. My thinking was that if I did not have to resize the files too much, then they would stay clean and have smooth outlines. The advantage to me to discover that I could use .jpg files is that I have a huge collection of fonts in my Affinity software, which can be used for vector, bitmap and publishing activities.
Luban was found to open correctly after I had followed Wayne’s advice. I opened each file as a B&W image and sized the image to 39mm square. The line direction was set at horizontal and I changed the density setting to 10. The jog speed was left at 3000 mm/min and I set the work speed to 800 mm/min. the power was set to 50% and fixed. (I am using the 1600mW laser module)
The g-code files were generated and then saved to file. All of the files were saved to a USB stick and although I work with MacOs, the stick was formatted to DOS-FAT32. I ran all of the files from the stick and they required anything from 3 minutes to 6 minutes depending on the complexity of the letter shape.
The results should speak for themselves. There is no discernible edge burn or smoke staining and these look like a high quality item. Thank you Snapmaker team and all of the people on the forum who have helped and guided me. Thank you all.