General build instructions for KDE packages can be found at 
  https://community.kde.org/Guidelines_and_HOWTOs/Build_from_source

Specific build instructions for Umbrello can be found at 
  http://umbrello.kde.org/installation.php

In short, here is how to build current git master on Linux :
  git clone git://anongit.kde.org/umbrello  
  cd umbrello
  mkdir build
  cd build
  cmake -DCMAKE_INSTALL_PREFIX=$HOME/umbrello -DCMAKE_BUILD_TYPE=Debug  ../

When building/running on KF5, make sure that the "kio" package is installed.
For details see https://bugs.kde.org/show_bug.cgi?id=361479#c3

