The device at the top rear of the machine is the tabulator ...
... which is set, cleared, and activated using this three-function lever:
Pure mechanical poetry ... by the way, the carriage runs and returns silently and smoothly.
The control above the dealer's nameplate is mysterious. If you press the left side down, both sides go down, and you activate the margin release. (By the way, the right margin will stop typing but can still be bypassed by the spacebar or carriage release, on which point you can start typing again.) If you press the right side down, only that side is activated — to do what? I haven't figured it out.
The front plate comes down to give access to the typebars, and
a decal in English provides the inch width of the necessary ribbon.