You don't need much to get started playing PathfinderLITE. Download the required documents and any recommended documents using the links at the bottom of this page. Read over the documents; especially any with CORE in the file name. Get some friends together and game on!
Please do not use any of the other Md20 specific plug-ins; only use documents that have PathfinderLITE in their name. This is because great care has been taken to not overpower characters or knock other features out of balance. PathfinderLITE is now a self contained rule-set that no longer refers to Md20.