Stop summing the whole table column

Hello folks! I am new to PowerBI and have been trying to input a filtered value into a text box, however, the value I am trying to get is being automatically summed by PowerBI and I have no clue how to avoid it. Is it in the Power Query part? I saw some answers here when using a card for example that you can prevent summarization when inputting a field. However, I don't have this option with a text box. I think this image explains well what I am trying to accomplish: 

Thanks in advance!