Scene setup steps:

Click the button "Create collections"

Objects that are needed to be optimized move to the “on_subd“ collection. There all objects will have subdivision and multiresolution modifiers optimized. It is not necessary to add subdivision modifiers to all objects in the “on_subd“ collection. The addon adds them automatically. But if the multiresolution modifier is needed to use, it must to be added before otherwise, the addon will add a subdivision modifier instead. Objects in the “off_subd“ collection will have subdivision and multiresolution modifiers removed. Objects outside these collections will not be affected.

   Set variables for optimization:

a.       max_subd_global(int,min=1,max=11)- Maximum subdivision levels allowed for rendering.

b.       viewport_max_subd(int,min=1,max=11)- Maximum subdivision levels allowed in viewport.

c.       add_subd_global(int,min=1,max=5)- Added subdivision level to current subdivision level. Negative values do subtraction. Value after addition is clamped between 0 and max subdivision. Use only, if meshes do have not enough detail or too much detail for the majority of meshes on_subd collection.

d.       subd_drop_factor_global(float,min=0.1,max=1.5)- How quickly subdivision levels drop depending on the distance from the camera.

e.       apply_subd(float,min=0.1, max=1.0)- Minimum factor to add modifier.

f.        verts_not_subd(int,min=50, max=50000)- Maximum vertices count allowed to add modifier.

   Create custom properties for specific objects(if different settings are needed for some objects):

a.       max_subd(int) - Maximum subdivision levels allowed for rendering.

b.       add_subd(int) - Added subdivision level to current subdivision level. Negative values do subtraction. Value after addition is clamped between 0 and max subdivision. Use only, if meshes do have not enough detail or too much detail for the majority of meshes on_subd collection.

c.       subd_drop_factor(float) - How quickly subdivision levels drop depending on the distance from the camera.

Copy custom properties to selected objects(If it is needed to add same custom property to many objects, you can copy it from active to selected)

Update/Refresh the scene

Scene updates automatically after changing global variables. Use Update/refresh scene, if there are added new custom properties(or their values are changed). Also, if there are camera settings changed, use 

Update/refresh scene.

Bake animations(If scene is animated).

Before baking animations make sure that all collections are turned on.Before baking animations make sure that all collections are turned on.

Not necessary to bake all animation at once. There is possibility to bake it by shorter segments. Change scene start and end frame to bake segment you want.