If you have not already, please join the DiFX-Users mailing list - to do this, go to https://listmgr.nrao.edu/mailman/listinfo/difx-users and sign up.
You might find it enlightening to browse the SVN source tree.
Read the Reference Manual which has a lot of detail about the NRAO installation of DiFX and a lot of information about the helper programs for configuring the correlator and managing the output.
The (now-defunct) forum on the old DiFX-users Google Groups page (https://groups.google.com/forum/#!forum/difx-users) might also have useful information, so feel free to swing past there and search old threads for answers to questions you might have.
How to correlate using different binaries on different cluster members
How to correlate directly off a Mark5 unit
How to achieve very high spectral resolution
How to correlate targets which are near-field objects such as spacecraft
mpifxcorr documentation
vex2difx documentation
difx2fits documentation
difx2mark4 and hops documentation
difxfilterbank documentation
difx_monitor documentation
Utilities documentation
difxmessage logging information
vdifio vdif access libraries
espresso (scripts for managing file based correlation) documentation
difxdb (database extension of difx)
startdifx documentation
polconvert documentation
Subversion tips and tricks
Description of correlator amplitude scaling
Complex-sampled signals and vex files - an explanation of how to configure DiFX input when using complex-sampled data.
DiFX2.0 explained - the differences between DiFX1.5 and DiFX2.0
Description of the cluster definition file
A description of the way channelisation works for upper and lower sideband data
Notes on optimizing the machine file
Using DiFX with non-power of two FFTs (beta!)
The DiFX release process (how to tag)
Chris' summary of routine call sequence
Using plplot and installation instructions
Current status of VDIF support in DiFX
Plot DiFX extracted pulse cal data
Material for DiFX exercises at the IVS school 2016
List of steps to take for VFASTR when a DiFX version is bumped
The DiFX memory size/datarate calculator (now available as a C program in the difxio library)