Each of you will have the opportunity to teach a portion of a class period.
Some of you may have attended conferences and seen several conference presentations. Mini-lectures are about teaching, not about conference presentation. A conference presentation simply summarizes the important parts of a paper to an expert audience. Teaching is much more than that. You need to first understand the technical material (this may require reading some background material too). Then, you need to find a way to explain the material to your colleagues. Again, focus on the problem; if your audience does not understand the problem, they won't care about the solution. Don't be afraid to teach material that is in some of the background that you might have read. It is more important that your colleagues (other students) learn something from your 30 minute lecture, than it is that you cover all the material in the paper.