If you are having trouble, feel free to send Mike Stecker (@mikestecker) a message on Slack or, you can email him. Make sure you tell me what email software you are using if you need help importing the HTML.
how to insert html signature in [your program here]
Instructions below were taken from: htmlsignature.com/how-to-create-and-install-a-html-email-signature-in-google-gmail
CTRL-C) to your clipboard.
CTRL-V) the email signature design you have stored in the clipboard.
Mail.app is a little trickier but, not hard once you understand how to do it. The links below show you using their sample files, just use the one generated from this form instead.