Welcome! 
I saw your post on FB somewhere and was about to reply with,
LightBurn provides documentation to assist you in getting setup and running. Common Grbl Setups - LightBurn Software Documentation
Do this project to get a good overview, Beginner Walkthrough - LightBurn Software Documentation
And this is also worth review, Configuring a 3018 CNC (or other CNC-based laser) for use with LightBurn