Barry,

First: Turn on your scanner.
Second: Start/Launch Photoshop.
Third: In Photoshop click on File and scroll down to Import

Fourth: Click on Epson

This is what mine looks like after Import:

Set the dpi where the red arrow is.
It will be 300 dpi when you import it again, until you change it.

Fifth: Close Epson Scan Import (don't close Photoshop).
Sixth: Adjust/Save your scan.

Let me know if I misread your question.