First of all, choose a configuration name, e.g. WED12, AMU12, PERIANT025, etc, and save it, i.e.: export CONFIG='WED12'
Compile for a new configuration, e.g. the WED12 configuration (you can have several ones)
Choose fppkeys prior to compilation (see NEMO documentations or examples in existing configurations, e.g. MY_NEMO/NEMOGCM/CONFIG/AMM12/cpp_AMM12.fcm), and compile, e.g. :
NB: if you recompile, it is recommended to remove these directories: rm -rf ${CONFIG}/WORK ${CONFIG}/BLD;cd ..
NEMO maketools
Compile REBUILD_NEMO (used to recombine outputs at the end of the jobs):