Walking bass is a style - not a setting. Is there a slpit point on your piano? Can you assign the left hand part of the keyboard to a bass tone? These are questions that must be answered before you can practice a walking bass.
The simplest pattern is a simple scale - played down from the root note. eg:
C - B -A - G ( repeat )
another easy and popular walking line is the boogie woogie. This is made up of the 5 tones of an arpeggiated Dominant 7th chord:
Try:
C - E - G - Bb - C - Bb - G - E - C (again)
After a while it will become second nature and you will have a ball creating your own "grooves" and "kicks" by syncing the left & right hand together in a tight rhythmic pattern. That's what I do most of the night. The arranger and the sequencer are about 30% of my material - the rest is "Me on bass! "