Hiya, welcome to the forum.
If you have a standard fixed license key, you can activate 3 computers at a time. Please read here for more details: How the LightBurn license works – LightBurn Software
Here you will find minimum computer systems requirements for LightBurn: Installation & Setup - LightBurn Documentation
You will need to take some measurements to determine what camera is right for your laser. You can then use the camera selection tool table to see which camera best suits your situation: Which LightBurn Camera Should I Get?
You can see what’s changed between the versions on our website or forum.