How do I copy Lighening entries from one laptop to another. Lightening is installed on both laptops

Can we step back first? Lightning is an addon that is used within Thunderbird, so I take it that Thunderbird is installed too? Is this a one-off, one-time event? Are you just starting with a new computer and want it set up to work like the old one? In this case, I'd recommend copying the Thunderbird profile from the old computer to the new. If you have reasons for not moving all the email-related stuff across, then I think you could export calendar data to a file and import it into the new computer. I'd have to do some research on this as I've never tried it myself. If you're going to carry on using both computers and sharing calendar data is to be an ongoing thing, then I'd urge you to look into using an online calendar which both of your Lightnings can synchronise to. I use Google Calendar for this, but there are others that will work too. I don't know of any simple way to do sharing without using synchronization.