Did your ancestors come from the area called Neumark (today Poland)? Let me just introduce some sources to you so you know where to start.
You will find the villages and towns that belonged to the Neumark listed here. As many of the church and other records were destroyed in the last days of World War 2, secondary sources are very important. Therefore, you should definitely check the Neumark database. The many volunteers who helped fill this database with loads of information worked with many sources now being available online or in German libraries.
Also, an important source for researchers are the many Heritage Books of the Neumark, that can be found online.
If you want to look for records in Polish archives (and more and more is available online), you can search the website of the Polish State Archives.
German archives holding information from the Neumark are the Landeshauptarchiv Brandenburg in Potsdam and the Geheimes Staatsarchiv in Berlin, the latter is important if your ancestors were among the settlers who colonized the Neumark. These archives do not have any records available online, except for those who were filmed by Familysearch/Ancestry.