Basic Smear Settings
The basic smear is the only smear you get in the free version; in the full version, you get this and the full smear.
The settings of the basic smear nodegroup are relatively simple.

Object/Collection Settings¶
Every Auto Smear nodegroup has these settings, and they determine what will get smears. In almost all cases the user does not have to worry about these settings as they will be handled by the addon.
Speed Threshold¶
The minimum distance the mesh needs to travel to smear.
Use Vertex Group/Vertex Group¶
Use Vertex Group will enable the use of the Vertex Group Setting, when you check it you will see that setting stop being greyed out.
To use a vertex group, make sure you have a vertex group on the object that is being smeared, and then in the geometry nodes settings, type the exact name of the vertex group.
The menu won't auto-populate with vertex groups but as long as you type the exact name (case-sensitive) it will work.
Noise Settings¶
Static Noise¶
Checking this will make the noise static, not changing based on the mesh position. Can be useful for slower movements.
Strength¶
The strength of the noise displacement. Positive values displace towards the previous frame, negative values displace in the opposite direction.
Scale¶
Scale of the base noise octave.
Detail¶
Number of noise octaves. This can have a fractional part, in which case a blend is performed (e.g. a Detail of 2.5 results in a 50% blend between 2 and 3 octaves).
Roughness¶
Blend between a smoother noise pattern and a rougher one with sharper peaks.
Noise Settings
The descriptions of these settings are from the blender docs, they are just the normal settings on a noise texture.