What is Karel and user frame

Karel is an optional high-level programming language for Fanuc robots.
The basic language in Fanuc is TP (teach pendant).
I strongly encourage you to get familiar with the robot at TP level, before getting involved with Karel.

A user frame is a XYZ coordinate system defined by user, as opposed to the firm World frame.
More than one user frame may be defined.
The TCP (tool center point) actual position and motion target are described in the selected frame.