The website of Luftdaten.info has no english explanation or instructions on how to assemble the particle matter sensor, yet. But I made a rough translation and put it into a google doc. You can acess it here and if you want you can also make some changes.
For some english explanations of this project see my blog entry or look at this very good article in Open Source.
How to build a smog sensor with a ESP8266 microcontroller //cc @riedelwerk https://t.co/ME7ej8RehF
— a ka es (@a_ka_es) March 28, 2017
https://twitter.com/ssiekmann/status/846122433023164416
You might also try this incomplete git-hub description.