Create an in-memory pivot table using DAX Path functions

I've tried this solution for creating a P&L but got stuck at this step:

"When the parent-child accounts have all been setup the formula for getting the calculation for the "in-memory pivot table" is:

PivotAmount =
SUMX (
    Accounts;
    CALCULATE (
        SUM ( Facts[Amount] );
        FILTER (
            ALL ( Accounts );
            PATHCONTAINS ( Accounts[Path]; EARLIER ( Accounts[ID]; 1 ) )
        )
    )
)

‘Facts’ is the table where all the transactions are stored and ‘Accounts’ is the table with the list of accounts and parent id’s".

Do i have to put this Formula in a new Table or in a new Measure?

When i create a new Table i get the message "the expression specified in the query is not a valid table expression", when i create a new measure it only shows the Grandtotal of all lines.

Test

I find it really hard to create a P&L in Power BI, while for our organisation this report is one of the important reports available.

Are there other solutions for creating (sub)totals in a P&L?

Thank you in advance.