So I’m starting a new town with completely nothing. I’m still at the beginning stage and I can’t remember for the life of me: how do you unlock the town museum?
Yup, the museum is always there...just go into the downtown area where Nookling Junction and the post office are, past the train tracks. It's always on one end or the other of that little street of businesses.
That's very strange, because the museum requires no unlock in New Leaf. It's always there, at one end of the street of the 'downtown', though which end of town it'll be on depends on your town's default layout. You can expand the museum by adding a second floor, but the first floor should be there from day one. You can donate to the museum even before you become mayor...in fact, donating items to the museum is one of the ways you can gain approval in your effort to BECOME mayor.
Okay this is no doubt a really dumb question...but you did go to the downtown, right? You're not looking in your own village area where villager houses and ReTail and the bus station are, are you? Cuz if you ARE, then you have to cross the train tracks to go downtown to get to the area where the museum is.
That's probably not it, but just in case, since in Wild World the museum was right in your own town, iirc, where the villager houses and so on were.
Have you looked on both sides? The layout of Main Street changes depending on which side your beach is, so if you previously had a town with the beach on the opposite side, the Museum would be on the opposite side of your Main Street.