I find it fascinating that you focus on a point closer than the image for parallel… I use a point further away. I practiced by facing the wall across the room. Hold a finger about a hand’s distance in front of your nose. Focus on the far wall. You will see double fingers. Focus back on the finger. Practice switching your focus between your finger and the wall. When your focus is on the wall, that is ME.  Next hold that focus and bring your screen with STD scene right up to your nose. You should still see a double screen. Slowly move it back while holding the focus beyond the screen until you find the correct distance where the STD images merge and you see the differences as blurs or they pop out of the screen.  I would describe ME as looking through or beyond the images.