The shortest route to becoming a 747 pilot (First Officer) is to join an airline which operates this aircraft type, and offers a cadet training program. Singapore Airlines is one such company but gives preference to Singaporean nationals. Having said, they have hired non nationals in the past. There are others.
The cadet program will take a bit over two years to complete but if you are one of the higher achievers on the course you will end up in the right seat of a B-747. A command will take a lot longer.
You will need plenty of ambition, motivation and a large dose of luck to obtain a slot it but is achievable
Good luck in the process
