Since you are not asking a Game Design question but rather a question about how to use this website's features, this post has been moved out of the Game Design forum to our Comments, Suggestions, and Ideas forum. Good luck with your endeavors.

@finlay I think your best bet is to upload your Powerpoint file to Google Slides. Then make sure the file is Shared with anyone who has the link. Then share the link in the Game Design forum, along with clear questions as to what you hope to achieve by sharing your game ideas. Be advised, though, that nobody is going to make your ideas for you. If you want to recruit a team, best to do that in Hobby Project Classifieds.