Add the didi path to your Matlab path (without the subdirectories) and run the main function:
dd_basicproc
* SPM12
* Diffusion toolbox (http://sourceforge.net/projects/spmtools)
* BET (http://www.fmrib.ox.ac.uk/fsl/bet)
* Distributed computing toolbox (optional). See:
http://fieldtrip.fcdonders.nl/development/qsub