Once installed, open the Compositor Side-Panel, tweak the sliders & click 'Create Test Frame', which will generate a single frame for viewing in the Image Editor. You can create as many test frames as you like, once you're happy with the look of the Grain, select a Folder, set the number of frames you need and click Export Frames. 

Once it's done exporting, you can re-import the grain in a single click by hitting 'Composite Grain'. 

1. Download the ZIP.
2. Open Blender -> Edit -> Preferences. Click the 'Add-ons' Tab.
3. Click 'Install' and navigate to the downloaded ZIP. 
4. Once installed, check the Checkbox to activate it and save your Preferences.
5. The Grainy tab is available in the Compositor Side Panel (N Key).

The grains are generated with raw low-level math, there are no images used in the generation process. You are free to sell or give away any grains you create with Grainy.

Please use the Blender Marketplace contact form to get in touch and I'll get back to you ASAP.