The EMC is configured with files that are read at startup and used to override the compiled defaults. No real controller will likely use the compiled defaults, so you will certainly need to edit at least some of these files to reflect the specifics of your machine.
There are four files: emc.ini, emc.nml, tool.tbl, and emc.var. The first, emc.ini, contains all the machine parameters such as servo gains, scale factors, cycle times, units, etc. and will certainly need to be edited. emc.nml contains communication settings for shared memory and network ports you may need to override on your system, although it is likely that you can leave these settings alone. tool.tbl contains the tool information such as which pocket contains which tool, and the length and diameter for each tool. rs274ngc.var contains variables specific to the RS-274-NGC dialect of NC code, notably for setting the persistent numeric variables for the nine work coordinate systems.
The specific formats of each of these files is detailed in the following sections.