:editby default it is limited to the working directory: if you need to edit a file that is not under your working directory, you will need to specify its absolute path or the path relative to the working directory. In addition, you need to provide the necessary globes.
:find :edit, () , , path. path :find , :edit.
set path=,, , :e foo.
set path=** , :e **/foo, , - glob.
set path=.,** , .
set path=.,**,/path/to/some/central/vendor/directory ... ..