Jady,
Here goes.
Saucer & SKATE Targets
Game starts with bottom L (20K) already lit. Dropping the SKATE targets first time then lights the other "L" (30K), and also lights the bottom of the two star rollovers. If the ball then goes into the saucer (at this stage), you would score 50K points, as both "L" lights would be lit.
Dropping the SKATE targets a second time then lights the A (50K), and also lights the top of the two star rollovers. If the ball then goes into the saucer (at this stage), you would score 100K points, as both "L" lights and "A" light would be lit.
Dropping the SKATE targets a third time then lights the extra ball light. If the ball then goes into the saucer (at this stage), you would score 100K points, as well as the extra ball.
Dropping the SKATE targets a fourth time then lights one of the two outlane special lights (which alternate).
Note that once the ball goes into the saucer and collects the points, the B-A-L-L lights will reset to just the bottom "L" lit. Dropping the SKATE targets after this will once again build up as per above.
An unlit star rollover scores 100 points. A lit star rollover scores 1,000 points, and also advances the bonus by 1,000 points.
"A"/"B" Rollovers
Rolling over these scores 1,000 points (regardless of whether they are lit or not). They start off unlit. First time going over say "A" will then light "A", and subsequent rollovers over "A" will score the 1,000 points, plus will advance bonus 2,000 points each time. Getting both "A" and "B" lit will then light the spinner for 1,000 points.
There is also a combination of lighting the "A" and "B" lights, and dropping the SKATE targets (just once is needed for dropping the targets). Doing this will actually light the extra ball light for the saucer.
Also note that a lot of the above is dependent on dip switch setting. Behaviour (as per the manual) may alter depending on the settings.