A Vim plugin is a set of Vimscript files that are laid out in a certain directory structure. Before plugin managers became popular, Vim plugins were usually distributed as tarballs. Users would manually download the file and extract it in a single directory called ~/.vim, and Vim would load the files under the directory during startup.

This simplistic "download & unzip" method might work for a tiny number of plugins but the effectiveness of it degenerates quickly as the number of plugins grows. All the files from different plugins share the same directory structure and you can't easily tell which file is from which plugin of which version. The directory becomes a mess, and it's really hard to update or remove a certain plugin.

vim-plug, a modern Vim plugin manager, downloads plugins into separate directories for you and makes sure that they are loaded correctly. It allows you to easily update the plugins, review (and optionally revert) the changes, and remove the plugins that are no longer used.

vim-plug is distributed as a single Vim script file. All you have to do is to download the file in a directory so that Vim can load it.

See https://github.com/junegunn/vim-plug?tab=readme-ov-file#installation

With vim-plug, you declare the list of plugins you want to use in your Vim configuration file. It's ~/.vimrc for ordinary Vim, and ~/.config/nvim/init.vim for Neovim. The list should start with call plug#begin([PLUGIN_DIRECTORY]) and end with call plug#end(). PLUGIN_DIRECTORY is a placeholder for vim-plug's plugin directory. Please do not set it to a directory from runtimepath option. Do NOT set it to the autoload/ directory where plug.vim is.

" Plugin directory is optional
call plug#begin()

" Declare the list of plugins.
Plug 'tpope/vim-sensible'
Plug 'junegunn/seoul256.vim'

" List ends here. Plugins become visible to Vim after this call.
call plug#end()

After adding the above to the top of your Vim configuration file, reload it (:source ~/.vimrc) or restart Vim. Now run :PlugInstall to install the plugins.

Run :PlugUpdate to update the plugins. After the update is finished, you can review the changes by pressing D in the window. Or you can do it later by running :PlugDiff.

Updated plugins may have new bugs and no longer work correctly. With :PlugDiff command you can review the changes from the last :PlugUpdate and roll each plugin back to the previous state before the update by pressing X on each paragraph.

1. Delete or comment out Plug commands for the plugins you want to remove.
2. Reload vimrc (:source ~/.vimrc) or restart Vim
3. Run :PlugClean. It will detect and remove undeclared plugins.