You can record your max 3 minute presentation for example using the zoom app in a single person session! We will explain how this can be done in Zoom, but there are other (free) applications you can use like OBS Studio (quite complicated though).
If you don’t have it already the zoom app for your desktop machine or phone can be downloaded for free at: https://zoom.us/download#client_4meeting.
Open the Zoom app, login and connect to zoom using your existing account or use a google, apple id or facebook account, select New meeting, select Connect audio and video. Set camera and microphone, put them on and test whether you can record a small piece. Open powerpoint or your favourite presenting app and load your presentation and start it. Select share screen in the zoom app and select your presentation screen. Now start the recording in Zoom, by pressing the recording button next to the Share screen button (or press Alt-R) and do your presentation, if you leave your webcam that will be shown in the upper right corner of the presentation file. When ready stop the recording by the right control window button or Alt-R and end the zoom session (for all). It will now create the recorded session as mp4 video file. Zoom will open in Windows explorer at the folder where the recording is saved. You can check the file, for example with the VLC media player to see whether you are happy and as soon as this is true please upload the mp4 file renamed, using your abstract number as the file name, for example ‘41.mp4’.