Assemblies
An assembly's Structure tab starts with its figures: how many parts and sub-assemblies (and how many of them are different), its volume, size and centre of gravity.
Under them is the structure itself. Tree shows the instances as the model has them, each with its document, the version and revision it uses, and its quantity. Parts list flattens the tree into one row per part with the total quantity. That's the bill of material.
An orange mark means something has moved on. rev B on a row means a newer revision of that document exists. inside means something further down the tree is behind. When updates are waiting, a note above the structure lists them, and Update references writes the newer versions into the draft. The assembly is then built again.
Export makes the whole assembly into one OFB or STEP file. It runs as a job; the file shows up under Files when it's done.