When introducing networks into the classroom I really think relating the subject to networks that students can see and actually travel on like the transport network is a great tangible and visible concept for primary students to grasp what a network is and how they work. I found this great teaching activity resource on the Digital Technologies Hub website that steps you through the learning sequence: https://www.digitaltechnologieshub.edu.au/teachers/lesson-ideas/computer-chatter-1

The area I live in doesn't have a local train network, however if I was teaching this lesson I would adjust my lesson to use the local bus transport network.

Picture taken from Microsoft Word Stock Images 'Internet network'.