How Do I change the GLOBAL maximum file upload size?

Admin-general preferences i think...but if you search the topic some of us have had difficulty doing this when we wanted to increase it...I did - couldn't for the life of me get it to stay big enough for a pdf file I wanted to upload...I think I ended up using downloads and putting the file there with a link...not sure...You could be being limited by your server.

best advice - run a search on the question of maximum file sizes.

Normally this is set on the server itself, so unless you are able to use php.ini to control the size, you will need to ask your hosting provider to raise the limit.