The Neptune 4 Max bed dies not come with any alignment guides. That makes placing the 420x420 magnetic plate somewhat challenging at times. Just a drop of super glue or your favorite adhesive on the flat top and hold it in place for 30 seconds. Just don’t glue your fingers!!! You will need to clone it three times, five times, or seven times depending how many edges you want to align. It should be the exact height of the magnetic plate and bed together. Be careful on the right side of the bed as it is slightly closer to the Z Axis Frame Support! If your printer flow is too high your back wall may be too thick, just sand the outer wall facing the frame. I suggest ASA, ABS, or PETG filament for strength and heat resistance.