Update setup instructions

Still a lot of information is missing, but at least it's progress.

README.md

@@ -1,14 +1,74 @@
 # Laniakea Spark
 [![Build & Test](https://github.com/lkhq/laniakea-spark/actions/workflows/python.yml/badge.svg)](https://github.com/lkhq/laniakea-spark/actions/workflows/python.yml)
 
-The generic Laniakea job runner and package builder
-Communicates with Lighthouse servers via ZeroMQ to fetch new jobs and report information.
+Spark is the generic Laniakea job runner and package build executor.
+It is able to perform a variety of tasks on Laniakea on build-farms, like building
+packages or distribution ISO images.
 
-## Setup
+Spark instances communicate with Lighthouse servers via ZeroMQ to fetch new jobs and
+report information. They auto-register with the master system, if they were provided
+with the right credentials for the respective instance.
 
-Minimum Debian release: 11.0 (Bullseye)
+## Setup Instructions
+
+Minimum required Debian release: 11.0 (Bullseye)
 
 ### Install dependencies
 ```Bash
-sudo apt install schroot python3-debian python3-zmq python3-setuptools gnupg dput-ng debspawn
+sudo apt install \
+	python3-debian \
+	python3-zmq \
+	python3-setuptools \
+	python3-firehose \
+	gnupg \
+	dput-ng \
+	debspawn
+```
+
+### Add lkspark user and group
+```Bash
+adduser --system --home=/var/lib/lkspark lkspark
+addgroup lkspark
+chown lkspark:lkspark /var/lib/lkspark
 ```
+
+### Write spark.toml
+
+Create `/etc/laniakea/spark.toml` with the respective information for your deployment:
+```toml
+LighthouseServer = 'tcp://master.example.org:5570'
+AcceptedJobs = [
+    'package-build',
+    'os-image-build'
+]
+MachineOwner = 'ACME Inc.'
+GpgKeyID = 'DEADBEEF<gpg_fingerprint>'
+```
+
+### Create RSA sign-only GnuPG key as lkspark user
+
+TODO
+
+### Make Debspawn images
+
+TODO
+
+### Restart spark
+
+TODO
+
+### Add GPG key to master
+
+TODO
+
+### Add server key to Spark
+
+TODO
+
+### Generate client certificate
+
+TODO
+
+### Add client certificate to master
+
+TODO