changing passenger airbag

[chisnau]

hi guys
any advice on how to change the passenger airbag on the dash would be most welcome
also is there anybody situated in the merseyside/lancashire area who has a lexia 3 to remove faults that keep flahing up ie tyres punctured, tyre censors missing ,service light
it is a c5 3ltr 2003
many thanks
ron