looking up from under the grill in bumper you should see 2 bolts, you will need to undo these and lift the bonnet a few inches and with a screwdriver release the catch, and open bonnet, but the catch is likley to be seized solid, if its not then spray it with WD40 and then slap copper ease or white grease all over it
if it was a mk 1 it would be alot easier