There are a few ways to see someone’s activity on Instagram. You can view their posts, follow them, or add them as a friend. To view their posts, open the app and click on the three lines in the top left corner of the screen. The first line will show all of your posts from that day, and the second line will show all of their posts from this day. The third line will show all of their posts from all days in the past. To follow someone, open the app and click on their name in the top left corner of the screen. To add someone as a friend, open the app and click on their name in the top left corner of the screen and select “Add.”