Sum based on a date range (customer recent orders)|Power Query|Excel Forum|My Online Training Hub

I have a table of customer orders with date and amount, I want to create a summary grouped by the customer name that shows the orders in the last month and the orders for the 3 months previous to that to flag which customers are currently buying, but haven't bought this month.

I've created a summary that can show the total amount ordered and know how to get the first and last date but the SUM based on the last 30 days of orders has me stumped.  I know how to do this in SQL with a WHERE clause and this is probably an easy task but I'm a Power Query newbie.  Thanks!

Here's my query but I feel like doing this as a group is not the right way to achieve what I'm looking for...

let
Source = Excel.CurrentWorkbook(){[Name="Table2"]}[Content],
#"Changed Type" = Table.TransformColumnTypes(Source,{{"Customer", type text}, {"Order Date", type date}, {"Amount", Currency.Type}}),
#"Grouped Rows" = Table.Group(#"Changed Type", {"Customer"}, {{"Total Sales", each List.Sum([Amount]), type number}, {"First Order", each List.Min([Order Date]), type date}, {"Last Order", each List.Max([Order Date]), type date}})
in
#"Grouped Rows"