Meeting, we would have to assume they are very intelligent... at least socially and mechanically, and with a great understanding of mathematics, physics and all material sciences and biological sciences as well.
Socially, because no single individual could build a craft sufficient. Such would require the co-operation of members of an advanced social system... either voluntarily or through being forced. (Would truly intelligent beings willingly accept being forced?)
If really smart, I would think... they prefer to think for themselves and take on work voluntarily and co-operatively.
Mechanically, because the craft would be, after all, some kind of a machine, as we commonly recognize such. A vehicle.
Material sciences because... just think about it. Rocket Science to the maximum!
Physics... the same. Huge understanding of everything necessary, basically, just like here. Flight dynamics, stresses, etc. etc.
Biology and physiology, because of the hazards of space-travel and effects on sentient, physical bodies.
Some could argue that an alien body would be made of something not harmed by cosmic rays, x-rays, etc.
or that time wouldn't bother them because they had conquered it, or so on. Some would say aliens don't need bodies at all,
that they are mental entities who travel by thought or something. Well, this is all open to imagination...
A cup of tea!
It is well-realized that we have no clue! Tea may be poisonous or a serious drug to them.
For them to travel without provisions enough would be madness, unless they had some food-sustinence-energy conversion technology, (like pioneers who took a shotgun with them to convert four-legged energy to food)... and are they travelling randomly thru the vastness of space? Matter is rare in space and distances vast.
Did they set out knowing we are here? Are they embarked on a mission to seek out and discover whatever they may stumble upon? Would intelligent beings be content to wander around aimlessly?
Our greatest problem today... one of them, in my opinion, is that we are very territorial. The territory can be land, materials or ideas,
and we fight, and have for millions of years, to hold our little territory. Will aliens want our territory for themselves, being stronger and more advanced than us? Will they act like guests or like conquerers?
Will they take the planet's resources? No. Not to worry about that. Their abilities to extract any minerals or whatever from different worlds will be perfected. All earth has is a few pounds of gold and diamonds compared to entire carbon worlds made totally of diamond. Earth is small and hasn't got much, relatively... until it comes to it being JUST PERFECT FOR US! (how about that?)
But will we be herded into camps? Will we be used for food? Will we be selectively bred like cattle?
Minerals, gems, rocks and whatever is abundant in the universe. We SHOULD understand that life is the RAREST thing... that is what aliens would be attracted to. That is OUR question as well, isn't it? 'Is there life out there?' Not... are there electric toasters in space? We could care less about toasters and junk.
Everyone is attracted to 'life', and that's what we, and aliens, would want to know about.
So... they would look around and think about life. They would understand impermanence and change. They would comprehend pleasure and pain. They would relate to suffering, need and hunger. They would also understand compassion.
They would observe governments and businesses and militaries and ask, 'what are these humans doing and why?'
Aliens would be interested how history has shaped today's range of possible experience, and how forces in the world today will shape tomorrow. Would aliens perhaps try to inject some ideas or information which, in a few years time, like a seed growing into a good plant, alter patterns of understanding, thought; human doing and living on the planet?
I bet they could write a book or two when they get through!
Would aliens... how would they have evolved over time? Would they have left war-like tendencies behind?
Would they have to have developed war-like tendencies like humans, considering the human/animal evolutionary past history? Would they prefer to display a peaceful attitude and understanding?
As for ideas and concepts regarding a creator-being or a god.... We have no idea what they would think.
Let's say they discovered that these humans have many belief systems. First, they may try to explain and understand what 'belief' is. They would probably want to understand something that virtually all peoples are involved in, to some extent.
Certainly there is a difference between 'belief' and the reality of something. Like... 'I believe we have enough space-ship gas to make it to the next planet', versus... 'Oops! We just ran out of gas, fool!'
Anyway, that might be first; to refine or define some meanings we assume we understand perfectly, but perhaps don't, only realizing our half-understanding of so much, actually. Aliens would have to tease apart the tangle of information so they could
begin to get a clear understanding. They would have to be scholars of scholars and even go beyond that.
And the word, 'faith'. They would want to know about that and understand it well. They would have had to have 'faith' in their ship to travel in it, no doubt. Perhaps they would want to know about, 'blind faith', and just what it might mean also. They couldn't have blind faith in all their wonderous, advanced technology... what would be needed was a technician who knew all about it, could troubleshoot and repair and even create new, if need be.
Afterlife would be a concept to probe. They might discover why humans have this idea and why it seems so important.
They would wonder about these humans, clearly related to and evolved from primates, but who consider themselves so totally different from all other life-forms, with something they call a 'soul' and the thing of 'eternal life'. What would thorough investigations reveal? What would be discovered? Would certain 'unpleasant truths' be discovered which humans refuse to admit to themselves?
Would we end up hating aliens for things they may discover which we aren't ready to?
Would we want them to go away? Would they have overstayed their welcome if they make us nervous?
Would we embrace them if they could supply the missing piece of the puzzle for us, which would bring peace and happiness?
Would we like to BAN them?
Maybe we could write a book as well... a book of imaginary contact with aliens.
What if WE ARE THOSE ALIENS on a journey, attempting to KNOW OURSELVES?
Do we know ourselves? Can we know anyone else until we understad ourselves well? Really well?
Anyway, all imaginations aside... How about that cup of tea?