documentclass[%BCOR=20mm,
]{tudscrbook}
setlength{oddsidemargin}{-12pt}
setlength{evensidemargin}{47pt}

usepackage{layout}
usepackage{blindtext}

begin{document}
layout
blinddocument
end{document}

documentclass[%
% BCOR=20mm,
  cdgeometry=custom
]{tudscrbook}

%setlength{oddsidemargin}{-12pt}
%setlength{evensidemargin}{47pt}
geometry{margin=2cm} % change values for your needs, read texdoc geometry!!!

usepackage{layout}
usepackage{blindtext}

begin{document}
layout
blinddocument
end{document}