Transferring all Lightroom data from Windows to Apple iMac

So I began my use of Lightroom on my Windows Dell laptop.  I have recently upgraded to an Apple iMac and have re downloaded the Lightroom program. However, I'm now stuck with a fresh slate in LR which I don't want.  How do I sync over all of my presets and images from my old account to my new iMac?

-Nadine