I do not think you can use FNDLOAD for users. The documentation of FNDLOAD is in Appendix C "Loaders" in the "Oracle Applications System Administrator's Guide".
As for examples, here is one for downloading all menus starting with XX:
FNDLOAD apps/apps 0 Y DOWNLOAD $FND_TOP/patch/115/import/afsload.lct menus.ldt MENU MENU_NAME=XX%
and here is one for downloading all responsibilities starting with XX:
FNDLOAD apps/apps 0 Y DOWNLOAD $FND_TOP/patch/115/import/afscursp.lct responsibilities.ldt FND_RESPONSIBILITY RESP_KEY=XX%
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Aleksander Dragnes