ScreenSharing a section from current meeting - for teaching Taiji through zoom

Currently, I’m teaching Taiji(Tai Chi) through online private sessions. I have a Pro account so I can record the sessions but when explaining to a student something they’re doing wrong I’d like to screenshare the last 20 seconds or so of the recorded meeting and talk to them about what they’re doing wrong so they can see it. But I have no idea how to go about doing this or if it can be developed into an app or something. Do any of you guys have ideas on how this can be accomplished?