el-get allows you to install and manage elisp code for Emacs. It supports lots of differents types of sources and is able to install them, update them and remove them, but more importantly it will init them for you.
That means it will care about require ing the features you need, load ing the files, setting the Info paths so that C-h i shows the new documentation you now depend on, and finally call your own :after function for you to setup the extension. Or call it a package.
These details are provided for information only. No information here is legal advice and should not be used as such.