if I use "Mobile Tethering" and share a network with my computer, will the network admin be able to see my activity on my computer?? If the Admin can see my activity, is there any other ways to "hide" my activity on my computer??
Yes, Its possible to do so. Here, I am adding a link that can guide you to the process. I am sure that will help you out in the pursuit of getting your query answered without any bias. https://www.quora.com/How-can-I-check-what-people-are-surfing-using-my-WiFi