Construct a musical piece by amalgamating the designated alphabetical representation and the supplied musical theme.
X:1
L:1/4
Q:3/4=90
M:6/4
K:Bb
['f3 d3/2 c/ B A2 B c2', 'c2 d']  
X:1
L:1/4
Q:3/4=90
M:6/4
K:Bb
 f3 d3/2 c/ B | A2 B c2 d | e f g f d2 | c3 B3 :: c2 d G A B | c A2 G2 F | f2 g d e f | B f2 g2 a | 
 b3 f3/2 e/ d | c2 d e2 f | g3 f d2 | c3 B2 :|  