It took me about 2 hours and 12 minutes to set it up though.
1. Install Java JRE.
2. Download a Photon release .jar file.
3. Download and extract the search index (this part took 2 hours and 7 minutes, even with pbzip2, no idea why).
4. java -jar photon-0.5.0.jar
5. Wait 4 seconds for it to start up.
Kudos to Komoot for building this.