xcelsius and sap bw

Hello, i'm new at xcelsius and I have to modify an existing dashboard to connect it with a sap bw query.

I created the connection but i'm a bit lost in the definition. Actually I really dont know what link with the input filters and variables.

And the same for output variables, charcteristics and crosstab.

Is there a good tutorial to show how its linked with the excel embded sheet ?