How to Customise SharePoint List Alert Emails

I just found a, potentially, very useful feature of SharePoint Lists and Power Automate but I need some help to make the most of it.

Under the Automate drop-down in the modern experience list, there is an option to create ‘Rules’ instructing the list to perform certain actions when particular conditions are satisfied.

For Example: When [Date Column] = Todays Date, send email to [User Column].

This appears to work well and has the potential to save me a lot of work with Power Automate workflows if I can find the answer to one question: How can I customise the text of the email that is sent?