With so many references available, what do you mean?
Does that Abaqus version require ifort 11.0? If so, you can't count on an older ifort version. Any of those versions have been off support for quite a while.
One place to start is in the Abaqus documentation in the "Abaqus Analysis User's Guide", in section "18.1.1 User subroutines: overview". There is a good introduction to the command line syntax used to link a Fortran user subroutine to an Abaqus analysis. Also look in section "3. Job Execution" for some more information about the "user" command line option. Hopefully you have installed the on-line Abaqus documentation; if so then you can also search for key words like "Fortran" or "user subroutine" in the user's manuals to find more information.
