Filtering table before grouping using date slicer

Hi Anonymous  , thank you so much for responding to the post !

I have managed to replicate the example you gave.
So I created the separate date table and a measure in the base table. 
Am I also able to include the count as well in the CALCULATE(***) so that I know that my SUM was derived from so many number of transactions ?

The solution so far wont work for me as the end goal is to take the aggregated values and join them to a base table.
The main thing is that while this shows how we can filter a table based on a date then aggregate, we really want this to be either available in the modeling phase so that I can join a main table to the summary.
Is this possible to achieve this at modelling phase or in visualization phase ?

If its not, How can I achieve this so that the aggregated values from a seperate transaction table can be joined to a seperate main table based on oderID 

There are actually 2 detail tables that need to be summarized , and joined to the main table, each bringing a specific amount to do with the orderid.They both have dates as well.
Would the solution that works for joining 1 aggregated table to the main table be extnsible to work for both, in terms of filtering then aggregation 

Thank you !