1. Create Your PowerPoint Presentation: Use Microsoft PowerPoint or a free alternative like LibreOffice Impress or Google Slides to create your presentation.
2. Record Your Presentation: You’ll need a screen recording software to capture your PowerPoint presentation along with your voice narration. There are several free screen recording tools available, such as OBS Studio, ShareX, or even the built-in recording features in PowerPoint or Google Slides.
3. Edit Your Video: After recording your presentation, you may need to edit it. You can use free video editing software like Shotcut, DaVinci Resolve (free version), or Lightworks (free version) to edit your video, add transitions, and make any necessary adjustments.
4. Combine PowerPoint and Video: In your video editing software, you can overlay your PowerPoint slides on top of the video footage. This involves syncing the slides with your narration or video content. You can export your PowerPoint slides as image files and insert them into the video timeline.
5. Export Your Video: Once you’ve combined your PowerPoint presentation with the video, export the final video in a format suitable for uploading to YouTube. MP4 is a commonly used format for online videos.
6. Upload to YouTube: Go to YouTube, sign in with your Google account, and click the “Create” button to upload your video. You can add a title, description, tags, and other relevant information.
7. Publish on YouTube: Set your video’s privacy settings to either public, unlisted, or private, depending on your preference. Public videos can be viewed by anyone, unlisted videos can be viewed by those with the link, and private videos are only visible to specific people you invite.

Please note that the availability and features of software tools may have changed since my last update in September 2021. Be sure to check for the latest options and features of the software mentioned above and any new tools that may have emerged since then.

Additionally, YouTube’s policies and features may also have evolved, so make sure to review YouTube’s guidelines and settings for publishing videos.