readme: add install and usage

README.md

@@ -2,16 +2,88 @@
 
 The main control script for the Caelestia dotfiles.
 
+<details><summary id="dependencies">External dependencies</summary>
+
+-   [`libnotfy`](https://gitlab.gnome.org/GNOME/libnotify) - sending notifications
+-   [`swappy`](https://github.com/jtheoof/swappy) - screenshot editor
+-   [`grim`](https://gitlab.freedesktop.org/emersion/grim) - taking screenshots
+-   [`dart-sass`](https://github.com/sass/dart-sass) - discord theming
+-   [`app2unit`](https://github.com/Vladimir-csp/app2unit) - launching apps
+-   [`wl-clipboard`](https://github.com/bugaevc/wl-clipboard) - copying to clipboard
+-   [`slurp`](https://github.com/emersion/slurp) - selecting an area
+-   [`wl-screenrec`](https://github.com/russelltg/wl-screenrec) - screen recording
+-   `glib2` - closing notifications
+-   `libpulse` - getting audio device
+-   [`cliphist`](https://github.com/sentriz/cliphist) - clipboard history
+-   [`fuzzel`](https://codeberg.org/dnkl/fuzzel) - clipboard history/emoji picker
+
+</details>
+
 ## Installation
 
-### Package manager
+### Package manager (recommended)
 
-TODO
+The cli is available from the AUR as `caelestia-cli-git`. To install it you can use
+an AUR helper like [`yay`](https://github.com/Jguer/yay), or manually download the
+PKGBUILD and run `makepkg -si`.
+
+e.g. using yay
+
+```sh
+yay -S caelestia-cli-git
+```
 
 ### Manual installation
 
-TODO
+Install all [dependencies](#dependencies), then install
+[`python-build`](https://github.com/pypa/build),
+[`python-installer`](https://github.com/pypa/installer),
+[`python-hatch`](https://github.com/pypa/hatch) and
+[`python-hatch-vcs`](https://github.com/ofek/hatch-vcs).
+
+e.g. via an AUR helper (yay)
+
+```sh
+yay -S libnotify swappy grim dart-sass app2unit wl-clipboard slurp wl-screenrec glib2 libpulse cliphist fuzzel python-build python-installer python-hatch python-hatch-vcs
+```
+
+Now, clone the repo, `cd` into it, build the wheel via `python -m build --wheel`
+and install it via `python -m installer dist/*.whl`. Then, to install the `fish`
+completions, copy the `completions/caelestia.fish` file to
+`/usr/share/fish/vendor_completions.d/caelestia.fish`.
+
+```sh
+git clone https://github.com/caelestia-dots/cli.git
+cd cli
+python -m build --wheel
+sudo python -m installer dist/*.whl
+sudo cp completions/caelestia.fish /usr/share/fish/vendor_completions.d/caelestia.fish
+```
 
 ## Usage
 
-TODO
+All subcommands/options can be explored via the help flag.
+
+```
+> caelestia -h
+usage: caelestia [-h] COMMAND ...
+
+Main control script for the Caelestia dotfiles
+
+options:
+  -h, --help    show this help message and exit
+
+subcommands:
+  valid subcommands
+
+  COMMAND       the subcommand to run
+    shell       start or message the shell
+    toggle      toggle a special workspace
+    scheme      manage the colour scheme
+    screenshot  take a screenshot
+    record      start a screen recording
+    clipboard   open clipboard history
+    emoji       emoji/glyph utilities
+    wallpaper   manage the wallpaper
+    pip         picture in picture utilities
+```