Exciting times! There is an art to steering a tiller boat. Small corrections on the tiller whilst aiming at a point in the distance will see you following a straight course better than constant small zig zags. Try and go out in calm conditions at first. Play with different throttle settings until you arrive at the one that gives you best speed for fuel consumption. It is easy to use too much throttle. Often a reduced throttle gives much better consumption and is quieter without losing much speed.
Look at the wake of the boat behind for an idea of how straight a course you are steering.
When it comes to weather, it's down to experience. Going straight into the waves can be wet, as can can running down wind across the waves. It's a learning curve alright....
Above all keep safe and don't plan on long distance trips at first. Take an anchor and oars and practice using them.
The most important thing is wear a life jacket, Avoid high speeds until you get a feel for the boat & avoid drastic course changes until you have some experience with the vessel. It will be a fun time.
Don't try turning round in a big wave. Go with it and wait because sooner or later there will be a brief quieter patch that will enable you to turn into wind safely. Avoid running into shallows where possible. The waves will become steeper and there will be less gap between crests. Wear a life jacket and wear the kill cord. It wouldn't do to be run over and killed by your own boat after it had chucked you into the drink.
If you can find someone who knows their way around the water to show you the way.
Go slowly until you know your safe routes (at all water levels).
Oars. I know some people don't pick up the oars from one year to the next but I think it's important to be able to row efficiently. OK you aren't going to want to row the length of Corrib but they might get you out of trouble. If the engine packs up you only have oars, get used to using them so you don't end up zig zagging backwards onto the jagged rocks when it all goes wrong one day!
Best of luck with your new Boat and Engine.
As you have never driven one before I would think the best option for you is to get someone with experience to show you the ropes.
I don't want to put a damper on your excitement but things can go downhill pretty quickly should you find yourself in a situation where you you have no idea what to do.
Weather conditions can change pretty quickly here in Ireland - a sudden squall can turn a nice day on the lake into something pretty nasty in minutes.
I've had my fair share of frights and lived to tell the tale - some have not been so lucky.