The following may help you in locating UI elements which may have confusing names such as "list box" or "tree menu":
http://images.akamai.steamusercontent.com/ugc/55484619582118393/2DD1E84FC567846672B305BD17DB474F61740F28/?interpolation=lanczos-none&output-format=jpeg&output-quality=95&fit=inside%7C637:358&composite-to=*,*%7C637:358&background-color=black
A "list box" is the 6th UI element on the 1st column of the image.
A "tree menu" is the 2nd UI element on the 2nd column of the image.
Many of the steps above require you to left-click on UI elements. It may be advisable to use a mouse to accomplish this.
For clarification, this is what a magazine looks like:
http://vignette3.wikia.nocookie.net/fallout/images/3/3e/Assault_carbine_extended_magazines.png/revision/latest?cb=20110207025854