How to attach files to email using KM macro?

I have a few reports that I send out every month. Although the attachments may be different each month, the email message is the same. I would like the ability to use a Keyboard Maestro macro to automate sending these reports by attaching the selected files to an email template by either selecting the files and using a keyboard shortcut or by dragging the files into a watched folder. I’m able to get the macro to generate the email template based on the triggers I’ve assigned but can’t get it to attach the files automatically. I’m sure it’s something simple that I’m missing but I’m not sure how to get the macro to attach the selected/dragged files to the email.

I’m new to automation and KM so I’m not sure which triggers to put into place to get it to do what I want. Anyone have any ideas?