OK well in that case its covered by the 1997-1999 manual.
There is only one Fuse involved and that protects both High beam and Low Beam, there is only one Relay involved and again that handles both High and Low beam from the Main switch, so if High beam is working then one of three possibilities;
1. Both bulbs have blown at the same time - not unheard of.
2. The Main switch has broken, and I don't think its easy to get at as its got to be removed from the steering column. I would guess a lower chance than 1. above !
3. The wiring has broken from the switch or to earth points for the lamps, again as both lamps are involved its unlikely but not impossible. I would guess lower chance than 2. above !
I would start with checking the lamps, perhaps the Offside one first as its easier to get at than the Nearside one, they can be a fiddle to
unclip see this thread it also covers choices for headlamps that are brighter as well.
If both High and Low beam aren't working then check the 30 Amp fuse in the little box connected to the rear of the Main battery terminal, third from right hand edge. If thats OK then check the relay as shown in the Photo above, Nearside wing, rear most relay of a possible 4 relays (note not all relays need be fitted but there are 4 positions).