Can you assist with DPI/PPI issue?

The math is killing me. I recently tried printing 5x7 photos and they came out really bad and pixelated. I changed the width and height resolutions to 2100x1500, but didn't realize that the DPI also had to be changed to a higher resolution (at least 200dpi I'm seeing? I left mine at 96dpi).

Before I waste my time and money trying it again, I thought I'd ask just to be sure. If I resize to 2100x1500 and change the dpi resolution to 300dpi, will my pictures print as I see them on my screen and not all blurry and pixelated?

Thanks.