If there are no incremental depth markings showing on the screen ... you can determine fish depth by turning on the Fish ID & FishTrack feature. That will give you a depth level to go by.
Also, run it in Manual mode & not Auto mode ... so you can tweak any settings that are needed, plus being able to look through the menu & see if there's anything listed that might put incremental depth marks down the right side of the screen. Most pics I've seen of this unit do not show incremental depth marks on the screen ... but, a few do ... so I'm thinking it may be possible to have them show up on the screen, but that feature may be buried somewhere in the menu
... cp