This is a nice tutorial, but I think there's a much easier way of cleaning the board in PS. Just draw a rectangle selection around the letters and type Backspace. When a pop-up windows shows up, choose "Content-aware fill" and then type Enter. This works in PS since many versions ago
a bit disappointed last step is not working at all with a text layer and i recreated the step like 6 times... so all the tutorial was useless for final result