Making a character walk through keyboard commands?

I currently have a character walking back and forth continuously. How can give the user the ability to do this by using the four keyboard arrow buttons. I haven’t been able to find anything about this in the Manual.

This the current code,

Create the four lerp intervals needed to walk back and forth 
ralphPosInterval1= ralphActor.posInterval(13,Point3(0,-10,0), startPos=Point3(0,10,0)) 
ralphPosInterval2= ralphActor.posInterval(13,Point3(0,10,0), startPos=Point3(0,-10,0)) 
ralphHprInterval1= ralphActor.hprInterval(3,Point3(180,0,0), startHpr=Point3(0,0,0)) 
ralphHprInterval2= ralphActor.hprInterval(3,Point3(0,0,0), startHpr=Point3(180,0,0)) 

#Create and play the sequence that coordinates the intervals 
ralphPace = Sequence(ralphPosInterval1, ralphHprInterval1, 
ralphPosInterval2, ralphHprInterval2, name = "ralphPace") 

Did you read the manual that comes with Panda yet?
It can be found in the folder samples. Tut-3 explains how to get inputs from the keyboard. So look in Panda3D-1.0.5\samples\Basic-Tutorials–Lesson-3-Events

Basically, you need to make your world a subclass of DirectObject:
class World(DirectObject):
This gives the class the ability to listen for and respond to events.

Then to define the action of a key, you use self.accept:
self.accept(“escape”, sys.exit) #Exit the program if escape is pressed
self.accept(“mouse1”, self.handleMouseClick)
self.accept(“e”, self.handleKeyE)

where handleMouseClick and handleKeyE are functions that define what to do, when the mouse is pressed and when E is pressed.

You can use the arrows as well: arrow_up etc.

And even listen for when the key is released: arrow_up-up
(-up means released)

Have fun.