want to use a theme , advice on changes

[sabishi]

hi. I am browsing the downloadable "free" mybb themes.. I want to use one but it comes with a license.. I am not sure what I can actually change? I want to be able to customize it eg: change banner image. forum topics etc.
theme:
https://community.mybb.com/mods.php?action=view&pid=389

it has this license. GPL Version 3, 29 June 2007

[.m.]

you can make required changes to all parts of the theme except the theme coder credits part at the footer.

[sabishi]

thanks for the quick answer mate!