I have question as described in the title - how can I add residues to protein, with the PyMol Builder, and mark them as non-organized? PyMol gives options to add them as beta-sheets or alpha-helixes, nothing else.
I guess you could first build an extended chain, then adjust the torsion angles using the torsion command (https://pymolwiki.org/index.php/Torsion). Of course, while the ideal torsion angles for helices and beta strands are defined, the angles for random coil are variable, although mostly constrained to allowed regions of the ramachandran plot. You would also have to take care of not having the chain clashing with itself.