readme: add usage example

README.md

@@ -14,3 +14,28 @@ Simply add this repo to your sources by running the following command
 sudo curl -fsSL https://linux.sia.tech/debian/gpg | sudo gpg --dearmor -o /usr/share/keyrings/siafoundation.gpg
 echo "deb [signed-by=/usr/share/keyrings/siafoundation.gpg] https://linux.sia.tech/debian stable main" | sudo tee -a /etc/apt/sources.list.d/siafoundation.list
 ```
+
+After that, you can install any of the available packages (e.g. `hostd`) like this:
+
+```bash
+# install
+$ sudo apt install hostd
+```
+
+All packages also ship with a systemd service that you can use to keep hostd
+running in the background:
+
+```bash
+# create working dir
+$ sudo mkdir -p /var/lib/hostd
+$ cd /var/lib/hostd
+
+# configure hostd
+$ hostd config
+
+# enable hostd systemd service
+$ sudo apt enable --now hostd
+```
+
+If you want to install a different package just replace `hostd` in the
+commands with a different package name.