Raspberry Pi GPIO - email

Just got my Raspberry Pi set up. Now trying to create my first flow. Have managed to successfully generate/send emails when an input pin (GPIO3) changes state but I've got a couple of problems I'm struggling to resolve.
Firstly, the single input is generating 2 emails, first one for the 0 and second for the 1. I understand why just don't know how to prevent it. Also, I cant see where or how to edit the email messages from pi/3 0 and pi/3 1 to what I'd like to see. Looked at as many Youtubes and forums as possible but to no avail.
Any help greatly appreciated. Thanks.

To stop both transitions from triggering the email, feed the gpio In node through a Switch node configured to test the payload and send it to output 1 if it is 1 and ignore it otherwise. If that gives the wrong transition then obviously test for 0 instead.
I don't know what you mean by editing the message.

Many thanks Colin. Yes I did try using a switch node. I'll try it again. The email messages that are being passed thru from the GPIO input come thru on to the emails as pi/3 in the subject (as I'm using Pin3) and 0 in the body. Have tried quite a few things but vant seem to change this..

What does the info tab say you have to do to set the subject line? How have you tried to do that?
In the Switch node make sure you select number 1 (or 0) and not string as the type. Number 1 is not the same as string "1".