Denis, perhaps if you go to full screen and look for the yellow blocks, and tackle on the maindeck, in way of the container crane, then you will be able to see how the cranes are pulled ashore on rails.
Rails on board the vessel are lined up with temporary rails ashore, and then, when tide and ship are at the same 'height' it's a 10 minute job to winch them ashore (if all goes to plan!).
The simplicity of design of the crane's bogies means that once ashore, and in the correct location over the permanent rails, the massive crane is raised by hydraulic jacks, the bogies are swung through 90 degrees and then with a bit of jiggery-pokery, the crane is lowered down onto the permanent rails. Et voila!
However, in the real world, getting the crane off the ship is the comparitively easy part, then the fun begins with getting said crane to desired position.
Once on the permanent rails, the commisssioning team from ZPMC take over. The crane(s) is/are moved to a quiet, screened off area of the quay -often at the quay end, if practicable and the testing and finishing off commences.
This has taken three months to complete in some cases where remedial work is required. (say no more!)