There is an arm here. It's a little hard to make out these details. I believe what happens is this section is attached to this arm, this outstanding arm. Then the arm slides back in, drawing the tower section with it. In other words, the hook can only pick this piece up and bring it close to the crane. It can't get any closer. Now you need to kind of an outrigger to come out, grab onto the piece and slide it horizontally in place. I'm not sure you can make it out on your screen, but there is an ironworker here guiding the bottom of the tower to make sure it comes into this space cleanly.
Here's another photo, different crane different location and this crane to begin with. If we look at the crane for a minute, this has a luffing boom. It does not have that horizontal boom. This is a higher capacity crane. You can see this extension in place, and the crane is lifting a section of the tower. It's going to attach to that extension. By means of that extension, it will be drawn inside the open space.
I've explained to you how the upper part of the crane is wider than the tower. It telescopes over the tower, and it can ride up. Then when you're completed your construction, it can ride down. Having said all that, why isn't that evident in this photo? Why isn't the top section wider than the rest of the tower? Well, this, this crane does not climb. This crane has been assembled by another crane. Another crane has lifted it up there and lift it up the other pieces and assembled it in place. That's as high as this crane will ever go. You will pass many tower cranes that have this kind of a look. They are not climbing cranes at all. They've been assembled when the construction project is over. This big crane will come back again and disassemble them. Here's this very shaky video.