Who can tell us how the towers of tall buildings are erected?

According to my understanding, the question you asked has two possible meanings:

The first one is: how to install the tower crane for vertical transportation during construction? The answer is as follows.

The tower cranes used in the construction of high-rise buildings are all jack-ups, and their towers are all connected by a series of standard tower sections through bolts. When the building is not under construction, first assemble the lower tower section with the truck crane, and install a series of structures such as the boom and cab. Then with the construction of the building, the tower crane can lift the rotating part of the tower crane through its own hydraulic mechanism, and lift the standard tower section to the gap where the rotating part rises for installation.

The second question is: how is the external scaffold erected during construction? The answer is as follows.

Scaffolds in high-rise buildings generally use steel pipes connected by fasteners, and most of them are set up manually. In the initial stage of building construction, scaffolding is located on the ground. When the construction reaches a certain height, steel beams are embedded in the building and extend out of the wall, and the scaffolding above is supported on these extended steel beams.