First, choose the measure and dimension that you want to analyse and put them into the columns and rows sections. (e.g. Sales - Row, Region - Column)
Next, create a set based on the first dimension that you chose to analyse by right clicking on the field -> going to 'create' -> then selecting set in the menu
Then, create a calculated field via the drop-down arrow menu next to the search bar on the 'Data' tab.
Type in the following IF statement which includes your first chosen dimension (dimension 1) and the next dimension that you want to further drill down with (dimension 2) then apply it.
IF [dimension 1 Set] THEN [dimension 2]
ELSE ' '
Go on 'Worksheet' on the top menu and select 'Actions' -> Go onto 'Add Action' and select 'Change Set Values'.
In the top drop-down menu select 'Drill Down Set Action' and make sure to run the action on select. In the Target Set section, make sure the correct data source has been chosen and select the set that you made previously.
Also make sure that running the action will assign values to set and that clearing the section will remove all values from the set then click OK.
And there we have it! You can now select your first dimension in the view and it will drill down to your second chosen dimension.
This graph is a good option for when you want to make your bar chart more compact and easier to navigate as opposed to having hundreds of bars.
Hope this helps you in the future!