Bernau bei Berlin is extremely easy to reach from Berlin. S-Bahn line S2 runs from central Berlin (Potsdamer Platz, Alexanderplatz, Gesundbrunnen) directly to Bernau in around 40 minutes. Trains run every 10 minutes during the day. The journey is covered by the Berlin ABC zone ticket.
Regional trains (RE3) also stop at Bernau on their way north from Berlin Hauptbahnhof. They are faster but less frequent. There is no airport near Bernau — Berlin Brandenburg Airport (BER) is about 50km south, so the train via central Berlin is always the sensible option. By car, Bernau is directly on the A11 motorway, about 25km from central Berlin via the B2.