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Ahh the good old days. I did enjoy working on tower cranes.
& yes they are self climbing. If you look closely you will notice that the top few m of tower under the main deck is wider than the rest. This is the "Climbing Frame".
The crane itself is not actually attached to the main tower, but to the climbing frame, which inturn fits like a sock over the main tower.
hydraulic rams called "flippers" grab the top of the main tower & push down, litterally lifting the crane body up off the tower for the distance of half of the climbing frame.
So the whole main crane is actually flopping around on 2 hydraulic rams & held reasonably vertical by the climbing frame.
Then the crane drops the hook to the ground & hoists up another section of tower. The boom is raised to almost vertical so that the new tower section is brought in right next to the tower just under the crane body.
THEN comes the fun part.
The Crane Crew (usually 8 people) are climbing in & around the tower & climbing frame. A "needle" or steel beam with a small manual hoist on it protrudes from the climbing frame (look at the tower of the 2nd crane, you can see the needle sticking out) & the crane crew must transfer the new tower section from the hook of the crane to the hook of the hoist on the needle.
Then they drag the hoist with the tower section attached in under the crane body through a hole in the side of the climbing frame & bolt it to the top of the existing tower.
The flippers relax & rest the crane down onto the top of the slightly higher tower.
Then the flippers grab the top of the new tower section & the whole process starts again.
In an average AU city where the cranes are no where near as high, a good crane crew will install 1 tower section every 30 mins.
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