How do you fit a cam belt on vauxhall corsa 1.4 ls?

There's really not enough space on this site to answer this (or any cambelt replacement question) I would suggest that you get the Haynes Manual for your vehicle and gen up on it (possibly try local library to see if it's within your scope) I did my wifes Fiesta but had to buy special tools for resetting the cams. Haynes will give you a good idea of everything you will need, so you can price the job beforehand as well. I'm not a Haynes seller, just know that they will show you how to do the job right. With the right tools & equipment and endless cups of tea it will take about a day!