chore: add Installation section to README.md

README.md

@@ -9,7 +9,27 @@ A theme for [web-greeter](https://github.com/JezerM/web-greeter) / [nody-greeter
 
 ## Installation
 
-// TODO
+1. Install packages and build
+
+```sh
+$ pnpm i --frozen-lockfile
+$ pnpm build
+
+```
+
+2. Copy the `dist` directory to `/usr/share/web-greeter/themes/<theme-name>`
+
+```sh
+$ sudo cp -r ./dist /usr/share/web-greeter/themes/<theme-name>
+```
+
+3. Set the theme name in `/etc/lightdm/web-greeter.yml`
+
+```diff_yml:/etc/lightdm/web-greeter.yml
+greeter:
+-  theme: <other-theme-name>
++  theme: <theme-name>
+```
 
 ## Development