To manually add a plugin for php language to vim
0. vim plugins are of different types, (i) syntax (ii) indent etc.
1. create a folder like ~/.vim/indent or ~/.vim/syntax
2. collect the plugin for php.
Plugins generally have a name like php.vim.
Two different php.vim shall be available, one for syntax and one for indent.
3. put respective php.vim in respective folder.
4. when vim package is installed, it has its plugins in /usr/share/vim/ folder.
5. more info here (http://vimdoc.sourceforge.net/htmldoc/filetype.html)