I am currently working on a couple of how-to’s. This forum software is very easy to use once you get the hang of it, but a couple of things are a little hidden.
Go to your profile, by clicking on your name. Either on the top of the page, or to your left where the users are. Then go to the profile tab, and then change avatar. First click on Browse image, then confirm by clicking Upload image. After it has uploaded, you can crop and scale to make it a nice square.