Grille : the plastic thing on the front of the car between the headlights where the radiator gets it's air. To remove it, open the hood ( bonnet - you didn't say where you were located ) and remove the 4 8 mm screws from the top of it. Grasp it firmly about 6 inches either side of center and pull straight out.
You will then be able to see the 2 horns mounted to the center pedestal with 10 mm nuts.
Unplug the slip-on connectors, remove the horns, then you can touch one horn post to one battery terminal and use a short piece of wire to run from the other horn terminal to the other battery terminal ( like I said - ear plugs are nice ).

If either or both horns work, then the problem is in :
1. the horn switch(s) on the steering wheel.
2. the horn relay / fuses in the RCM ( module in the black box by the battery - RCM is the one closest to the engine ).
3. wiring.
( you are aware that the horn only works with the ignition switch in the on/run position, right ? - (( unless you did tighed1's "me so horney" mod ))

As to manuals, please click on the link in my signature ....