Kaltura is great for recording lectures and screensharing. You can also use Zoom to do this. It works well for recording short video responses to students that save to the cloud through Zoom. You can share the video with them in discussion posts or as feedback on a journal assignment as a short link that they can follow. Since it is recorded to Zoom's cloud storage, your students will be able to go back and watch it multiple times if they want to, for reference. This short video gives instructions on how to do this.