How to display ACF Custom Field in Query Loop

I am opening a new thread since the following has been closed https://projectdmc.org/support/topic/custom-field-in-query-loop/

I tried the solution, but unable to pull in the information that I want. The option Post Meta comes under the label “Background Image Source”. I am not sure if this is the right place to dig in!

Still I tried that and put the field name in the box below. Nothing happened. I don’t know how I can link an element in the layout with the field value I need to display.

I am very new to Block Themes and FSE!