Produce your own video
Many will produce for the first time a prerecorded (screencast) research talk. While that might sound difficult - it's not! There are plenty of ways of doing so, here are some simple suggestions. You will find many more if you do a quick web search for "produce screen cast".
Disclaimer: The organizers are probabilists and statisticians, no computer expert is involved. As such no questions concerning IT problems (production, upload, etc.) can be answered, please approach your colleagues or local IT experts of your institution in case of problems.
Download the free zoom version from zoom.us. Open your presentation (for instance symposium.pdf) in your preferred pdf-viewer and start a zoom session. Click the green share screen buttom in the zoom client and choose your presentation. If you like your face being recorded start the video, if not stop the video. Make sure your microphone is not muted. Now you are ready for the presentation: Click the recording buttom and record "locally" (the video will be stored on your computer) and start talking and scrolling through the presentation. At the end of the presentation click stop recording. That's it! Once you end the zoom session the video will be converted. Wait a moment (or two) and a window opens with your video in mp4 format. Please try to open the video (perhaps also with a different computer) to make sure the video was properly stored.
The simplest way to create your talk is via screen recording which is built into your operation system. Note that screen recording does not compress the videos automatically, they will be extremely large and should be compressed.
There is plenty of software to produce screencasts. Here is a short list of further tools that you might want to try:
YouTube live video
VLC Media Player