Everything related to our species’ survival (e.g. climate change, prison for humanity, etc.) and expansion/colonization across the Universe (not only our solar system) can be discussed here.
So! The first thing that we, humans, need to colonize planets is to colonize the moon, while also terraforming Earth (i.e. repairing human damage made to our home planet). We also need to take back our space junk to refine and reuse it before it is too late.
The Moon is a hostile natural satellite, for there is no to little atmosphere and it has a very low gravity. We constantly need to do regular physical exercise (too bad for my physical education class in high school) if we live up there and we also need a concealed base before the terraforming.