According to the British Council, level B1 corresponds to independent users of the language, i.e. those who have the necessary fluency to communicate without effort with native speakers. It is important to bear in mind that the Common European Framework of Reference for Languages (CEFRL) is the system that defines and explains the different levels of oral and written expression and comprehension for languages such as English.
One of the main challenges for B1 level teachers is to teach listening comprehension when not frequenting the same physical classroom every week. Here is a good bank of listening activities with audio files and worksheets to practice this skill with your young learners. Enjoy!