What are some issues you might have adding audio?

PowerPoint

If you add it and it's a very large file, you will have to put the file on your USB stick before you attach it to the PowerPoint, because otherwise when you bring your show to present, the sound clip path will not be found, However if it is small enough it will just be saved as part of the PowerPoint, but I would suggest for safety sake just keeping the sound file on your USB because you never know.

You might run into the issue of the sound at your presentation location not working, but check all the possible sound options, there will be one on the computer task bar, and one for external speakers, but there may even be a volume option on some computers that have an application for multiple projection options.