How to add a reminder note to a meeting in Outlook?

Dear all,

I need to add a reminder note to a meeting in Outlook. Sometimes, there are some additional topics and information that come up before a meeting (even after I have scheduled it). This note should open up by itself while I join the meeting (or the meeting takes place). This way I am remembered by the system about the topics that need to be highlighted during the meeting. Is there any way to do this? Any add-on to outlook or any built-in way to do this? I know that I can already modify the invite to add some information without sending this to the attendees. However, this is not really what I am looking for because I would need to open the email to read this. On the other hand, I want this reminder to popup (by itself) while the meeting is taking place.

Thank you.