If you need info there's guides from the Asociación de Guías de Puerto Plata (Puerto Plata Guide Association) positioned in strategic corners throughout the city. They can help you out finding sights, recommending places to eat and things to do. You'll recognize them by their light yellow shirt.
Puerto Plata (Silver Port) is nice town with many resorts and clubs in the area, places to visit include a fortress, Mount Isabel de Torres, the Amber Museum and of course the many beaches in the area. Puerto Plata has its international airport and bus lines to Cabarete, Sosua, Santiago and other places in the Dominican.
Founded in 1503 by Christophor Columbus!
The full name is San Felipe de Puerto Plata, but almost nobody knows it.