Power BI Beginner

Hello, I am relatively new to power bi. i wanted to create a visual that shows the progression of total bank facility value for 34 banks from 2015 till 2021, for 3 seperate types of clients. I am using 7 different tables, have already cleaned the data and have a general idea on how to use the program.

i visualise the table as follows: 

it starts with each Bank total value(15-21), then by drilling down it should show the progression of each bank over the 7 year period. 

i tried to create a heirarchy using the 7 columns of values of 1 segment from 2015 till 2021 but it wont let me. 

i have already created links between each sheet based on the names of the banks as they are the same in each year, yet it wont allow me to drag and drop the relative feilds to create a hierarchy. what am i missing? 

Thank you!