Hi,

What exactly is "Select Chain" for "Offset Entities" command?

http://help.solidworks.com/2012/English/SolidWorks/sldworks/t_Select_Chain.htm:
Select Chain
You can select a chain of entities attached to the selected entity in both directions until a branch is encountered. 
To select a chain of sketch entities: 
Right-click a sketch entity and choose Select Chain.   The entities of sketch geometry such as rectangles and polygons are selected. If the geometry includes branches, the chain stops at the branch. You can continue the selection manually.  
You can hold Ctrl and select multiple chains. 

I searched on the web as for images and video examples but didn't find a pertinent example. Could someone tell me what this option actually does?

Qi