@MrAl
Perfect! The picture helps a lot.
Yes, I understand the adjustment. PowerApps is not a development platform, it is a world of difference from a coding language. Some adjustment required!
So, here's what I am seeing, and I'm not sure it's what you really want, you've added a DataCard to your Form and chose the Author/'Created by' column. PowerApps has chosen for you to make this a ComboBox control. Kind of worthless...you cannot change or assign the 'Created by' column of a SharePoint item, so why bother?
So let's leave that for the moment and go back - your original request was to display the Author name and email address. Since you cannot change that, there is no other need than a label to display it.
Taking that into account:
1) get rid of the Created By data card in your form.

2) add a custom data card to the form

3) Add a Label control to your Custom DataCard (click the data card and then the Insert controls, choose a Label from the Insert ribbon)
4) Set the Text property of the Label to : ThisItem.'Created By'.DisplayName & " " & ThisItem.'Created By'.Email
That should give you what you want...feel free to adjust accordingly.