You need to put all of that in a code component and make it a variable. Then you can put that variable in the text box. So in the code component: feedbackText = ''.join(key_Resp.keys) and $feedbackText in the box.
So you mention “text box” and “box”. Which of these was the box I was typing in in the image I posted and where can I find the other box? Btw thank you for helping out.
Okay I typed the code in the custom code box. And then I typed the $feedbackText in the text box. The letters are not even showing up. I’m not sure what I am doing wrong.
Your original approach will work, without the need for a code component. Just remove the randomly placed $ from the middle of the expression and put it at the beginning. A $ symbol is not itself part of valid Python syntax. Rather, it is just an instruction to Builder itself to treat everything that follows as a code expression, rather than as literal text.
The only other thing is that the keyboard component needs to be set-up appropriately – e.g. to store all keys and not to force the end of the routine.