getting here from Berlin Tegel Airport:
Taxi is about 30-40 minutes and around €30,00.
If you need to book a taxi to get back to the airport, the online booking service is Talixo:
https://talixo.de/en/
Or phone 030 30 30 30 (they speak English too).
There are numerous public transport connections, but probably the simplest (not necessarily the fastest) is to take the TXL bus to Alexanderplatz and then the M4 tram (in the direction of Zingerstrasse), getting off at Albertinenstrasse. Allow an hour from Tegel Airport, although it can be quicker depending on the connections.
A single ticket is only €2,80 (or I suggest buying 4 for €9). These are valid throughout most of Berlin for 2 hours travel in the same direction on buses, trams, U-Bahn (subway) and S-Bahn (train).
There is a BVG (Berlin Public Transport) information desk in the airport (Terminal C). Depending on who is on the desk, they should be able (hopefully in English) to give you directions for the fastest connection, a map, and explain about tickets etc.
There's a journey planner on the BVG.de website (also in English), but I also find Google Maps is pretty comprehensive here too.