Using a Date Hierarchy in DAX

Hi All,

Apologies in advance, I am very new to Power BI and still trying to learn as much as I can.

I am trying to follow the example provided here: https://www.youtube.com/watch?v=L2ELtem2iGY&t=213s, more specifically the code shown below:

% Change = 
VAR CurrentValue = [Total Tickets]
VAR PreviousValue = 

SWITCH(
    TRUE(),
    ISINSCOPE('Date'[Date].[Day]), CALCULATE([Total Tickets]), DATEADD('Date'[Date], -1, DAY),
    ISINSCOPE('Date'[Date].[Month), CALCULATE([Total Tickets]), PARALLELPERIOD('Date'[Date], -1, MONTH),
    ISINSCOPE('Date'[Date].[Quarter], CALCULATE([Total Tickets]), PARALLELPERIOD('Date'[Date], -1, QUARTER),
    ISINSCOPE('Date'[Date].[Year], CALCULATE([Total Tickets]), PARALLELPERIOD('Date'[Date], -1, YEAR)
)
RETURN
DIVIDE(
    CurrentValue - PreviousValue,
    PreviousValue
)

However, I am struggling to be able to create a Hierarchy in my Date table that allows me to use a hierarchy in the following way: 'Date'[Date].[Day]'. Basically, I am unable to select the hierarchy I created in my DAX expression. 

The Hierarchy I have created is pictured below, and I am aware that it is named differently from the example above, however, I am still unable to select it ('Date'.[Date Hierarchy].[Day] etc.).

I have attempted to resolve this through multiple methods and none seem to work, so any help would be greatly appreciated!