Hi, I have written your formula, you can copy paste the following formula in the cell F2:
=IF(C2=D2,CONCATENATE(A2," & ", B2, " ", C2),IF(OR(B2="",B2=" "),CONCATENATE(A2, " ", C2),CONCATENATE(A2, " ", C2, " & ",B2," ", D2)))
Or send me message and I will send you the file to you. Best Regards