The Tibetan Buddhist Lama Temple (or Yonghegong Qiao) is northeast of the city center, close to the First Ring. To get here you had better take a taxi. The more intrepid travelers can also try the local public buses (116 and 106) and the metro (Yonghegong Station, Blue Line).
By the way, because Taxi rides are so cheap in Beijing, this is the number one way of moving around. The only problem you may encounter is that not many taxi drivers speak English. For this reason it is always recommended bringing the names of the places you want to visit, and the address of your hotel, written down in Chinese. If your taxi driver does not understand you, show him the piece of paper.
Buses are also good and efficient in Beijing. The problem is figuring out their routes. The metro is somewhat outdated, but it is the quickest. There are only three subway lines. The Blue Line, which follows, more or less, the First Ring. The Red Line, that goes from east to west. And the Yellow Line, that takes you to the areas in the north.