To install Otter Browser from source you need to have Qt SDK installed (http://qt-project.org/), at least version 5.2 of framework.

You can use either Qt Creator IDE to compile sources or execute following commands in directory containing otter.pro file:
mkdir build
cd build
qmake ../otter.pro
make
make install

Alternatively you can use CMake build system:
mkdir build
cd build
cmake ../
make
make install
