Don't worry about breaking anything.
What is the base vehicle of your California? Transporter/Caravelle, or Multivan?
If Multivan: lift up the darker grey trim (with the knobs for electric powered windows). Undo the wires (carefully). Unscrew 2 Philips screws (+) size P3. Unscrew 3 torx (*) screws (T25?) at the bottom. Lift up the inlay under the inner door handle, unscrew a torx T20 or T25. This is no problem. Then (works better in warmer temperatures) try to unclip about 6 to 8 clips that hold the door card to the door by prying with some hard plastic pryer.
If Transporter/Caravelle, it's about the same apart from the door handle trim. This is also lifting up but different from the Multivan. And then you won't have an inlay, so the screw in the middle will be visible through a hole above the under inlay. The rest should be the same.
If you have manual windows, unclip the winder...
Give it a go!