docs: update README with usage instructions

README.md

@@ -1,2 +1,33 @@
 # dotfiles
-My Dotfiles
+My Dotfiles managed by Gnu Stow
+
+## Usage:
+
+Clone this repository to ~/dotfiles with the following command:
+
+```sh
+git clone https://github.com/anthonyoteri/dotfiles ~/dotfiles
+
+```
+
+Change into the `~/dotfiles` directory and create the symlink tree using
+
+```sh
+stow .
+```
+
+## Adding a new file.
+
+Move the file into the `~/dotfiles` folder under the same directory structure
+as if the root of the repository were the home folder, then run `stow .` to
+create a symlink.
+
+## How it works
+
+The original files should live under the `~/dotfiles` directory in the same
+layout as they would appear in the home directory.  Gnu Stow will walk the
+directory tree, and create symlinks in the parent directory of any files it
+finds there.  E.g. `~/dotfiles/.foobar` will be mapped as a symlink to
+`~/.foobar`, and `~/dotfiles/some/path/.barfoo` will be mapped as a symlink
+to `~/some/path/.barfoo`.
+