The NIK Collection has been revived by DXO with a new version, but you can still find the old Google NIK, which is free. Which one you want to use is up to you, the presets work in both versions. There are two presets in there for Silver Efex and two for Analog Efex. There will be many more presets for the NIK Collection here, so keep an eye on this website.
Download the file
You can download the file by clicking the button below.
INSTALLING PRESETS IN THE NIK COLLECTION
In the article you get a step by step explanation. Enough information to see how to do this.