I know this may seem like a stupid question :
Should the text response and comparison be like:
Argument (topic sentence), evidence, explanation, link?
What do we write in the intro... like sign-post or whatnot
When they say "link" what are we linking to.. the topic sentence or the prompt?
I can't comment for comparison, so that was a part of English last year.
The typical structure of a text response is as you have pointed out it goes under different acronyms like TEEL.
But you don't have to strictly stick with it, it is mainly a guide for many people. I tend to have my explanation before my evidence, but that is just me. So i would stick to the structure if I was struggling to write, but experiment if you so wish.
As for the introduction, I'm assuming you want it for text response. I did sign-posting and was told that it was alright. I do wonder if that stopped me from getting better marks though.. something to ask other users like the Moderators of this board and the various guides on the sections.
As for the link, you would usually link it back to the topic sentence. But in your conclusion you would link to the prompt.