Populate email body from fields

Morning,

I'd like to be able to create a custom action to send an email and in that email I would like it to be populated with info from fields.

For example, the email would read something like:

Hello "First Name".  "Project Manager" has been assigned to the project "Project Name"...

I'd be grateful if someone can give me an example of how I can pull info from fields onto the email subject and body please.

Cheers