Want to replace painted front panel with stainless steel

The installation instructions and the Owner's Manual do not say how to replace the panel.  It may not be possible to change without replacing the entire door.
Look for trim near the top of the door that is attached by screws.  If the trim can be removed the old panel can be slid up and out and the new panel can be slid in.  Alternatively look for side trim piece(s) that might be removable allowing the panel to be slid in.