Subjugate them militarily, then set up missions to preach to them our gods, make them wear shoes and so forth.
The Question I have is what kind of gods have appeared in the nearby civilizations that can travel here, or is our planet unique (then we should conquer them)?
How often do planets make up such god stories? You could go there for your next lifetime, how'd you like that, instead of here?
You can imagine that there are a lot of civilizations that have come and gone and are to come and go, but if you narrow it down to civilizations that are happening right now, how far do you have to go to find good hard down to matter, material societies?
If there are "aliens", for values of "aliens"... there is no telling how weird (to us) they might be.
They could be a collective consciousness of some kind rather than individually self-aware. They might be very intelligent but think/act/live much slower (or faster) than we do because of biological processes.
They're more likely to look like a tardigrade than Mr. Spock. We might mistake them for trees or rocks or vermin at first.
They may not communicate with sound.
Even if we can learn each other's language (for wildly varying values of "language"), their thought processes might be so different from ours that real understanding could be nearly impossible.
They might have science but very little technology, depending on what resources they have available and their ability to manipulate same. (ie underwater species can't make fire, which is the beginning of technology by human understanding). Their tech might be so different we can't comprehend it.
They might not be very interested in us, or in any other species. They might think we are evil, savage, or incomprehensibly disorderly... or they might seem that way to us.
Most people, when they talk about "aliens", are imagining a more advanced version of US. That's probably not what we will find.
If we find any other intelligent, technological, communicative life in our galaxy at all. Thus far, the silence is deafening.