As part of a function, how could I create a variable number of sums one inside another based on a parameter?

I'm currently struggling on an assignment (probability class) which require creating a function (VBA excel) that contains a variable number of sums one inside the other based on a parameter. I'm not necessarly looking for the exact answer but just a similar a post or a better way to ask my question more clearly. I did make a function that show what the calculation would be if the parameter was 1,2 or 3. but how would i apply it if the parameter could be any natural number bigger then 3? If it sounds really complicated to do, just say it, I might be looking at the whole thing the wrong way.

Function prob_ruine_discret_exacte(u As Integer, k As Integer, prime As Integer, probas() As Variant) As Double
    'sum of probas = 1 with each value smaller than 1
    
    Dim sumProb(1 To k) As Variant
    Dim h(1 To k) As Long
    
   sumProb = 0
   
   If k = 1 Then
    For h(1) = 0 To WorksheetFunction.Min(u + prime, UBound(probas))
        sumProb(1) = sumProb(1) + probas(h(1))
    Next
   End If
   
    If k = 2 Then
        For h(2) = 0 To WorksheetFunction.Min(u + prime, UBound(probas))
            sumProb(2) = sumProb(2) + sumProb(1) * probas(u + prime - h(2))
            sumProb(1) = 0
            For h(1) = 0 To WorksheetFunction.Min(h(2) + prime, UBound(probas))
                sumProb(1) = sumProb(1) + probas(h(1))
            Next
        Next
   End If
   
   If k = 3 Then
        For h(3) = 0 To WorksheetFunction.Min(u + prime, UBound(probas))
            sumProb(3) = sumProb(3) + sumProb(2) * probas(u + prime - h(3))
            sumProb(2) = 0
            For h(2) = 0 To WorksheetFunction.Min(l + prime, UBound(probas))
                sumProb(2) = sumProb(2) + sumProb(1) * probas(l + prime - h(2))
                sumProb(1) = 0
                For h(1) = 0 To WorksheetFunction.Min(h(2) + prime, UBound(probas))
                    sumProb(1) = sumProb(1) + probas(h(1))
                Next
            Next
        Next
   End If
  prob_ruine_discret_exacte = 1 - (sumProb(k))
End Function