Should be in the owners manual; possibly in the service manual (which you'd have to buy, but IMO which you should have anyway.)
Not sure about Suzuki's but on my Yam it's a matter of tilting the motor up, removing a cap, and checking that the oil is pretty close to the level of the opening. I'd be surprised if the Suzy's any different.
If it's air (kind of a grinding sound as the rams cycle) you may be able to remedy by cycling from full down to up and back several times with a few minutes pause between to allow oil to settle. Take care not to overheat the tilt/trim motors, and might be good to have an AC powered charger on the batteries to keep them from draining.