I just noticed in another part of the forums that someone was trying to find the "triangles" in the binder (to expand/collapse a container document's sub-documents) as they went through the tutorial. They were running an older version of Windows that used + and - symbols for that sort of thing, rather than the arrows (similar to > and ^) that I'm seeing in the Beta/Windows 10.
I think most people are able to suss out what you mean by "triangle", but it's not an accurate descriptor for what is seen in Windows, and should maybe be noted or modified for the Beta tutorial.
FKA: robertdguthrie AKA: R Dale Guthrie, Robert, Mr. Obscure, and "Oh, it's you again".