How to integrate a Revue sign up form on Casper theme?

Hi everyone,
I would like to embed a sign up form for my newsletter, housed on Revue, on my website.

I am non-technical.

I do know that Revue gives their html code that I need to paste in my theme. I know how to download, edit and reupload

But I have no clue which file and WHERE exactly to paste it?
Any help or ideas are appreciated.
Edit: I think it is best that a prominent ‘subscribe’ button takes the clicker to my revue profile.
Thanks in advance!