The '!:1' is actually part of the alias (see the tcsh manpage for info, since those are tcsh aliases), where it substitutes the first argument from the ff into the find; for example, if you type in
ff test arguments
tcsh would expand the alias into
find . -name test -print
So ff is a simple 'find a file matching the first argument, starting in the current directory.'
The files alias finds all files (-type f) under the path given as the first argument.