Can anyone help me understand the parameters of the
subtotal function ?

For example, if in my code I want to do something like
this:

Worksheets("SubTotals").Range("D3: E900").Name = "MyRange"

MyRange.Subtotal GroupBy:=2, Function:=xlSum, _
TotalList:=2, Replace:=True, _
PageBreaks:=False, SummaryBelowData:=False

I'm OK with "Function", "Replace", "PageBreaks"
and "SummaryBelowData", but what is GroupBy and TotalList ?
What would the syntax be in this example ?
Thanks for your help.