Hi,
no worries
Take this script and put it somewhere ion your assets folder, simply by drag and dropping it.
this script complies with the action protocoles, so you will see it listed in playmaker Action browser just like any other actions you might find currently. At the top of the action's browser, you have a search field, type "drag" and you will get a short list of all actions which name contains "drag", you'll find that action "dragRigidBody", add that action to a state of a given Fsm, and this is how you will start working with it.
This action is totally embedded in Playmaker, so you don't need to add that script as a component or send messages, it's all done within playmaker for you, simply use it like any other actions.
now, for the sake of organization, I recommend you create a folder "PlayMaker Custom Actions" and have that script inside this, it will prevent crowding your project folder with junk scripts that do not belong there.
Does that male sense?
bye,
Jean