Ok, I will use myself as an example. If you click on my username, my "Member Card" will pop up, so when that happens, just click on the "Profile Page" link. When you go to my profile page, you'll see a tab called "Posts", so click on that. Scroll all the way to the bottom, and you'll see a link called "Find all threads by Baron". So click on that and there you go. Rinse and repeat for whatever member you need.