Construct a musical piece by amalgamating the designated alphabetical representation and the supplied musical theme.
X:1
L:1/8
M:2/2
K:Amin
['Bg g2 BAGB']  
X:1
L:1/8
M:2/2
K:Amin
|:"Am" ABcd e2 dc |"G" Bg g2 BAGB |"Am" ABcd e2 ed |"A" ^cA"G"BG"A" A2 A2 ::"Am" Aa a2 edcA | 
"G" Bg g2 BAGB |"Am" Aa a2"F" edcd |"A" ^cA"G"BG"A" A2 A2 :|  