Create Lane ⌥⌘N
The comparison between lanes in the Step Editor and tracks in the Tracks area is helpful.
The Step Editor should not be confused with the Step Sequencer.
The Step Editor allows you to create detailed editing windows for MIDI events that can contain lots of details that need to be attended to.
Logic Pro Step Editor Overview — Apple Support
Lane: Each MIDI event type, be it a note or MIDI controller, is arranged from top to bottom in horizontal lanes much like the track lanes shown in the Tracks area. The type of event shown, and controlled, on each lane is freely configurable. You do this by setting Lane parameters (for each lane) in the inspector. For more information, see Logic Pro lane parameters overview.