Ok I have made a logo for my forum, but I don't know how to upload it and swap it fo rthe massive MyBB logo...
Upload the file to the "images" folder of the forum. You can put it anywhere really, but I think keeping it in the images folder makes sense.
Next go to Admin CP > Themes > Modify Delete > Modify your default theme
Change the "Forum Logo" to the URL for your new logo.
i.e, if my image was at
www.example.com/images/newlogo.jpg then I would enter that.
I dont understand that...sorry