A quick guide to Analog Efex Pro 2 plugin and application from NIK / google
The key thing here is that you have to open an image and not all file types are supported. Once you have the JPG etc image open then you can add tools and filter settings to the image.
You can use the Analog Efex Pro 2 with just one tool such as basic adjustments (such as adding detail extraction and brightness and contrast etc) but you can add a whole range of different tools
The Analog Efex Pro 2 application (and plugin) comes with a range of tools such as
zoom and rotate blur
dirt and scratches
levels and curves.
You can use one or more of them but sadly you can't add multiple exposures and multiple lens vignette tools though the tool may allow multiple tweaks within the actual tool.
Click on the camera kit and you will see the basic tools but you will also see a selection of preset categories or groups for the Analog Efex Pro 2 and you can then click on those and you will see a selection of presets such as presets for motion and presets for double exposure etc. Click on a preset and the tools and settings will change on the right side and you will see the effect applied to the current image.
You can also click the little tick box beside each tool / settings and de-select if you don't want the basic adjustments for the Analog Efex Pro 2.
You can also go to the left side and perhaps add another tool via that list such as multi-lens if it is not included in the preset
Once you have set all your Analog Efex Pro settings and tools then you can click the + in the custom section on the left side and that will add a new custom preset with all the settings stored. You can then quickly click those to access all your tools instead of using the ones supplied with the Analog Efex Pro 2.
Most tools have a number of settings, some more than others and some have only visual tools such as frames or different light leaks etc (sadly there appears to be no way of adding your own to the application which is a pity).
You can click the vary which will randomize the settings such as brightness and contrast etc for the tool and you can then use the vary to try a whole range of different settings which can be saved to your preset
A really nice feature of the Analog Efex Pro 2 is that you can add control points to the image and vary settings (not all but many such as saturation and brightness) and set the size of influence for the control point. The control point means that you can set the brightness in a very localized area and not the entire image.
One thing you get when you apply the effect, the original layer and the effect layer and then you can always use the powerful blending modes to blend the effect and the original together (or perhaps use the opacity setting in the layers panel). Of course, you can also duplicate the effect layers and add other effects to that new layer and so on and build up all kinds of amazing analog efex pro 2 effects.
Of course, if you are running the effect as the plugin / filter, this does not apply to the standalone version
The analog efex pro 2 filter / plugin can be added to applications such as Photoshop and Affinity Photo and they can then be used with the other plugin tools and also the range of file types is a lot greater.
You can also add the filter multiple times as with the right image where the analog efex pro 2 presets have been applied multiple times
If you are using the application the only way to do this is to save the effect via the file menu and then re-open the image.
Another difference with the plugin / filter is that there is a brush option which is allows for painting on the effect so you get a truly localized effect. Of course, a simple way around that is to just apply the effect to a selection but the brush is a neat tool (even if it is oddly titled as a selective tool)
You can find other tutorials on plugins and tools for Photoshop etc such as Illustrator plugins from Astute graphics - symbol stipplism plugin and Adobe Illustrator wrinkle and distort filter / tool tutorial
Basic run through of Analog Efex Pro 2 application (youtube)