how to upgrade fuse box and wireing ?

In UK mains comes under Part P electrical installation/upgrade regulations and even if you did the job no electrician will sign off the work.

You havent a clue hence asking plus you haven't got the testing equipment to ensure it's safe and properly earthed and bonded......you will be liable for any accidents if wrongly installed and that could be in the holiday camp that's got bars instead of windows.

Life is short don't shorten in even more.

Bob
September 2011