The important thing to begin with is the name: this is Museu do Papel Moeda. In Portuguese, the title identifies it as a museum concerned with paper money. That is a wonderfully precise subject, because a banknote is never merely a means of payment: it is also printed design, official authority, and an everyday object passed from hand to hand.
While you remain on the pavement, use the building and its entrance as your bearings, and notice any lettering that carries the museum’s name. The name itself is the reliable introduction here. It tells you that this place is not simply labelled as a museum in general, but specifically as Museu do Papel Moeda.
It is worth letting that specificity register. Paper money joins public life to private routine: notes circulate through shops, homes, work, and travel, yet their production depends on institutions and careful design. Here, the Portuguese title puts that material object—the paper note—at the centre. Museu do Papel Moeda is the concise name to remember as you continue through Porto.