Creating Instance Sets
Creating an Instance Set is very simple in Unitscape, you simply select all the actors in your scene you want to be part of the instance set
and then right click in the content browser to create the instance set from selection as shown in this video:
Creating custom bounding box to prevent tiling gaps
It is advised you also create a bounding box for your instance set to make sure there will be no gaps between tiles of the instance set
(when the shape is larger than the instance set tiling will automatically be applied to it).
To create a custom bounding box you can use any sort of volume and make sure its name begins with "bounds" like shown here:
Actor attachment
You can attach actors to other actors to make sure the objects are grounded properly, like a bench with some items placed on it :
Hierarchical instance sets
Alternatively you can also use instance sets in other instance Sets and build a hierarchy this way (which achieves the same thing),
you can simply drag any instance set in the scene and make it part of another instance set simply by having it selected when you create
the new instance set asset: