for how much oil ,dip it drain it ,and measure how much came out ,at a guess probably 19litres 
1 oil filter
n/s of engine .and clean out sedimenter on tank
air filter behind o/s arch
steering is black resovoir with a filter in it 
should you really be doing a service ??,as you don't sound competent ,if you recognised the steering resovoir but haven't a clue about anything else ,i'd leave it for someone who knows what they are doing and can bleed a fuel system
                
 norb
                
 May 2011