I agree with Julian on this one.
We can only assume that the key signature has a Bb.
So, the notes in the Bb major chord are: [Bb,D,F]
And an eassy way to play that chord on the guitar would be like this..

e---------1---------
B---------3---------
G---------3----------
D---------X-----------
A---------X------------
E---------X------------