This conjunction has the same meaning as から presented in Lesson 10-7, but unlike から which appears within a sentence, だから is used at the beginning of the second sentence which expresses the result/effect.
この かんじは たいせつです。だから、おぼえて ください。
This kanji is important. Therefore, please memorize it.
この テープは よく ないです。だから、つかわないで ください。
This tape is not good. Therefore, please do not use it.