Add the following to plugins.vim
plugins.vim
Plug 'preservim/nerdtree' " file tree.
Add the following to %userprofile%\.config\vim\plug-config\nerdtree.vim and source it.
%userprofile%\.config\vim\plug-config\nerdtree.vim
Append these lines to the end
map <C-n> :NERDTreeToggle<CR>