Hello,
From your requirement what you are trying to achieve is that you are try to send an email to someone, on that email there will be a link. Upon clicking the link, your email field, subject and email body will be populated in a new mail window.
Am a very good tutoring and explaining things in Layman's terms. I can explain the steps for this in very simple steps with screenshots. if you want, then i can even create a video and send you the steps.
As far as i explained, i can assure you that i can really help you on this. Please send a private message and let me help you how to achieve this.
Thank you,
Christy.