Wroclaw has an amazing public transit system!  You can purchase tram and bus tickets at kiosks located near tram stations through out the city.  All kiosks have an english option. Children qualify for discounted tickets.  Below are some sites that may be helpful. 

For route planning,
Check out the super helpful website: "Jakdojade.pl"
This site shows timetables, the number of bus/tram you need to ride, and ticket prices
from where you want to depart to where you want to arrive.  They also have an app which allows you to access all information from your mobile and will track your route from door to door. 

General Public transportation's notes and tips :
(passengers ABC's, ticket types and prices and so on)
 http://www.wroclaw.pl/en/public-transport (English)

If you use public transportation a lot, you might want to get Urbancard.
http://www.urbancard.pl/en/index.html (English)