its covered in the search mate as its been posted loads
easiest way to do it is to go through the passenger footwell, pull the carpet down and there is a rubber bung, go through that into the engine bay mate
i didnt like the one at the footwell area as i had to cut through the material in my engine bay so i used one in the wiper area i have posted a pic of it in the last month so it will be there somewhere if you need to see it