Why can't I set up a key command to move the playhead?

I recently installed Logic Pro on a new mac. Can't find my old key command file from the previous computer, so I'm editing the protools preset list. But I want to be able to move the playhead with the arrow keys and when I search for "Playhead" under key commands there are no options for moving the playhead in any way, only shortcuts for moving things to the play head. I can't edit a key command that doesn't exist, can I? Why does this not exist?