You can’t. LightBurn supports a bunch of different laser systems, each with their own capabilities (speed, power, etc.). For Speed to be presented as a percentage, one has to know what 100% represents, in real terms, how far over how much time.
The numbers JDS provide are useless without knowing the top speed (expressed as Distance over Time) of the system they used when producing these recommendations.
We are wanting to help, but need a bit more info about your laser. We also need to know what you are wanting to produce and on what material. From there, we can offer some suggestions, specific to your system.
I also provide this chart that might work as a rough starting point for you: Boss Laser LASER SETTINGS - Boss Laser
You can also use a test file like the one below to test your settings for different materials. Once you have a setting dialed the way you want, you can save that setting into you ‘Materials Library’ for quick recall later when using that same material.