The trunions are the round black plastic lumps on each side of the tube which sit in the sides of the dob base. Like a an old cannon is mounted on its wooden carriage. They enable it to elevate They are the point of rotation and are usually about the centre of gravity. The springs are attached to a stud between the trunions.
Mine came (said proudly and with much importance
) with a crayford style 10:1 I love it. It is magic. Smooth and adjustable. (Many thanks to the kind chap on this forum who long ago sugested I download the equivalent Orion Manual.) My old Northstar has a plastic rack & pinion type which was hopeless. I ended up getting an electric acufocuser to give me fine control. Still had lots of image shift when moving.