Develop a musical composition using the outlined alphabetical depiction of the structure and the provided theme.
X:1
L:1/8
M:2/4
K:Amin
['G TEDEG TA2 G>A |{A} Bc/B/ (TAG)', '|{B} d3 d']  
X:1
L:1/8
M:2/4
K:Amin
"_Slow" G | TEDEG | TA2 G>A |{A} Bc/B/ (TAG) |{G} d3 d | (Ted)(e^f) | g2 (g/a/b) | G2 Te(d/B/) | 
 A3 :: B | GB d(e/^f/) | (g>a) ba/b/ | Tg(e/g/){e} dB |{B} d3 d | (Ted)(e^f) | gGga | baTg^f | 
 e3 ^f | gGga | b(a/b/) Tge | g(e/g/){e} TdB |{B} d3 d | (ed)(e^f) | g2 (g/a/b) | G2 Ted/B/ | A3 :|  