Implement decoder using simplified SOP
From what you have reached for the simplified SOP, you can see that "D" is present in both terms. So that can hint you to use it as the Enable input for the decoder, as the enable input would be AND ed with each minterm. Using D as the enable input leaves only B and E to be used as the inputs to S1 and S0; so you can assign them to the inputs arbitrarily(either (S1 = B, S0 = E) or (S0 = E, S1 = B). Then you just have to build Z using the outputs of the decoder(based on the S1 and S0 you have chosen).

Expanding what you have reached for the SOP, you get:(Oi is the i-th output of the decoder)

Z = D(BE + B') = D(BE + B'E + B'E') = O0 + O1 + O3

It appears that the Z marked on the image in your question is the complement of the Z in the equation.