Programming a Function in VB
 

Can anyone tell me how to do program a function in VB, say with two rows of
three cells each? I want to create a "spread" function that spreads amounts
in row A across factors in row B, and returns the results in Row F. The
function would be used as: Results = spread (Amounts, Factors), where Amounts
is the named range for Row A, Factors is the named range for Row B, and
Results in the named range for Row F:
i.e.,
Row A: a1, a2, a3 (input data)
Row B: b1, b2, b3 (input data)
Row C: a1*b1,a1*b2,a1*b3
Row D: 0,a2*b1,a2*b2,a2*b3
Row E: 0,0,a3*b1,a3*b2,a3*b3
RowF: c1+d1+e1,c2+d2+e2,c3+d3+e3,d4+e4,e5