What did Harappan trade involve?

Harappan trade involved the exchange of goods both within the civilization and with regions beyond. The Harappans traded items like beads, pottery, metals, and precious stones, as well as agricultural products like grain. They traded with distant places like Mesopotamia, where goods such as lapis lazuli, copper, and timber were exchanged. The evidence of seals and standardized weights shows the presence of a well-organized trading system. Harappan cities such as Mohenjo-Daro and Harappa were important centers for this thriving trade. The extensive trade networks helped in the spread of Harappan culture and goods.

This question related to Chapter 6 Social Science Class 6th NCERT.
From the Chapter 6. The Beginnings of Indian Civilisation.
Give answer according to your understanding.