Replacing Null Values in One Query with Values matching the same titled Row and Column in another?

So I essentially have a list of Retail Locations in power Bi that has sales data on a per location basis. The problem is we are trying to combine a manual source of data which has thousands of rows of data with an OLAP Cube Query. I originally was going to try and merge the Olap Cube data to fill in the 'null' values inside the manual data table, but this doesn't work the way I thought. Does anyone have a way I could write some DAX or M or MDX to recombine these values matching on like time and location and the name of the metric to build out this table? Thank you so much for anyones time i really appreciate it!