Dynamic embedded Iframes

Hey everyone.
I started use monday API and i came across with a question
I am creating an app which display a dashboard on the current loan status.
We came across of thinking to use monday for out tasks for each loan.
So in my python code i wrote that every new loan is generate with a new board of tasks that is fixed.
I created a template board and every time i duplicate it.
Now this is working and all fine, but the problem is in my frontend side,
I want to display the board that is connected to the same loan.
As i continue my search i saw the each board has it’s own id and i can retrive it with GraphQl
But there is another number that is generate in the board and i c’ant understand in the docs how can i find it or what is it.
Without it it’s impossible to load the board inside the iframe tag.
The number is also unique like id_board
Adding a url for refrence -

"<iframe src=“https://view.monday.com/embed/${loan.board_id}-a707a0c1027fda8ee6a0186fa1f7cf03?r=use1

Please help me to understand what is the number after the ${loan.board_id}