Explanation:

Assembling refers to the process of keeping the goods, purchased from different places, at a particular place. Assembling of goods is done only after they have been bought. Certain amount of assembling is done by the consumers also.
Example - We may buy the goods needed for household use from various sources and keep stock. A manufacturer may buy different kinds of raw materials from different sources and keep these in his stores. A trader also buys goods from different manufacturers and keeps these in his shop to be sold to consumers.