hi,
ok, just to make sure, Have you watched the videos and screencasts available? they are key to understanding what you are missing currently. Don't under estimate the power of these videos, even if they do not touch on your topic specifically, watch them with care because they give you the keys how playmaker is working.
Now, several things;
to retrieve a variable is only possible via an existing action, available in the Actions browser. This might sound obvious, but this is the first stop.
now, you have your action, fields can be in several "states", they can let you drag a gameObject onto it, or type a string, an int or a float, pick a color, BUT they can also let you reference a variable for that, simply click on the small icon on the right side of the field, and you will see *ALL* the variable of the field type that you can access.
SO: if you create a FsmGameObject Variable, and work on a "get position" action, if you want to get the position of a given gameObject, select "specfy GamObject" in the field "Game Object" and then you can either drag and drop one or click on the square icon to the right, the field will switch to "none", click on it, and you'll the GameObject variable you have created on this FSM plus the global gameObject variables too ( they'll be tagged "global" )
I think this might be where you are struggling right?
When you say "retrieve it from any menu", what do you mean by menu? variables are only settable and gettable within actions, or in the variable tab. not via menus.
Also, very important, when you create a variable, you need to then select it again, to set it up with a value. For example, if you create a gameObject var and want to reference a gameObject already, select it again, after you just created it and you'll be presented with a field where you can drag a gameObject onto it.
We'll get there!
Bye,
Jean