Create relationship between excel tables and prepare drill down chart

Hello,

I am new to PowerBI and trying to convert an Excel file to PowerBI graphs. At present we use a particular template to download data from our system. Below mentioned is the template format.

Unique ID | Name | Business Division | Office | Region | Total Bill | Payment Successful |

What we generally do is additional columns ( Manager and Designation ) and manually fill it based on our experience using values captured in "Business Division" and "Office" . This field is not present in application so we cannot generate a report and pull this information. 

I have imported two tables in Power BI, one whose columns I have mentioned before and another I have created manually in excel which contains following columns. This 2nd table has been independently created as the data in this data will be changed/refreshed every 15 days.

Business Division | Office | Manager | 

Let me how to join these two tables in PowerBI and create new column in 1st table named as "Current Manager". Multiple Business Division and Office and can have same manager. For e.g. "Logistics" division in "New York" office can have "ABC" manager whereas same "ABC" can be working for "Operations" division for "New Jersey". Based on this mapping I have to then create drill down charts which folds up something like this.

Region >> Office >> Manager >> Business Division >> Total Bill >> Payment Successul >> Name 

Can anyone help here?

Thanks,

AK