Hello, I'm very new to M code. Any help would be appreciated!

I have many tables with consistent naming convention and I need to append all of them. It's tedious to append them one by one manually through UI. I tried to look up but no one seems to have the same issue. This sounds like easy but I really couldn't get it work. Below is my code that I attempted to use but it keeps giving me error.

Simply put, I want to append all the tables that are already loaded in query with table name starts with "Test_".

Code:
let
    Source = Excel.CurrentWorkbook(){[Name="Test_Table14"]}[Content],
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Vendor", type text}, {"Item", type text}, {"Name", type text}, {"GL", Int64.Type}, {"Stream", type text}, {"Project", type text}, {"Status", type text}}),
    #"Appended Query" = Table.Combine({#"Changed Type", [Name = Text.StartsWith ("Test_")]})
in
    #"Appended Query"
Thank you!