To paste your HTML in here so we can see it you need to use the following method. Also, it is usually best to paste all of your HTML in here, not just the specific part you are working on.
To display your code in here you need to wrap it in triple back ticks. On a line by itself type three back ticks. Then on the first line below the three back ticks paste in your code. Then below your code on a new line type three more back ticks. The back tick on my keyboard is in the upper left just above the Tab key and below the Esc key. You may also be able to use Ctrl+e to automatically give you the triple back ticks while you are typing in the this editor and the cursor is on a line by itself. Alternatively, with the cursor on a line by itself, you can use the </> button above the editor to add the triple back ticks.
You want to use triple back ticks, not triple back slashes. If you can’t find the back tick on your keyboard then use the </> button in the menu editor bar that sits at the top of this editor.
It looks like you are trying to put the existing text input inside the new radio button input you are trying to add?
I would reset the step to get the original HTML back. You should not change anything that is already there. The only thing you are doing is adding a new radio button input above the existing text input. Look again at the radio button in the instructions for an example of how to add a radio button.