Playmaker Globals are stored in an asset: Assets\PlayMaker\Resources\PlayMakerGlobals.asset
If you want to move Globals to a new project you can just export this file in a unitypackage, and import it into the new project.
However, if the new project already has Globals, you need to be careful not to overwrite them!
In this case you need to use Main Menu > PlayMaker > Tools > Export Globals to export a copy of the Globals asset, and then Import Globals in the new project to merge the exported Globals into the project.