UK Car Repair: how to lock bottom pully, crank pulley, reply asap

Question
how to change a timing belt on a corsa b 1.4 16v and how to lock bottom pully so u can get the bolt out .
thanks reply asap plz

Answer
I'm not familiar with your car but often there is an access cover which allows you to hold the flywheel in position, many cars have a special tool for it. You also have to be able to lock the camshaft in position. If you turn the engine so that the timing marks on the crank pulley and those on the camshaft line up. You can lock them in that position, you will then be sure you haven't mistimed it.  Check that the marks actually do line up. Sometimes they can move out as the belt stretches.