Arduino monitoring Paypal Payments Answered

I could theoretically create a new email address exclusively for paypal alerts. I'm just such a newbie to arduino that I'm still trying to find an easy to follow way to do this. Most arduino email projects involve having the object send an email as opposed to do something when it receives one.

This one lights an LED when you get an email...

https://www.instructables.com/id/Arduino-Email-Ale...

...maybe it can be tweaked to filter the emails by sender before sending an alert?