The character (かがみ) is asking her sister to explain something, so she points to the textbook and says:「ここなんだけどね」. It's translated (presumably correctly?) as: "I'm talking about this". (The sister responds with 「かがみが わからないところは 私に分かるわけないでしょう」.)
What is the role of the ね particle here? I thought ね would reflect some feelings or thoughts that are (expected to be) shared between the two people. But this meaning doesn't seem to fit here.