Hi need help with forum widget side, not changing

Technical Details

Forum version : #phpBB3
Position : Founder
Concerned browser(s) : Mozilla Firefox
Who the problem concerns : All members
When the problem appeared : Hi can't change widget size
Forum link : http://dnsgtforum.forumotion.com/forum

Description of problem

Hi, i was wondering how do i reside the widget like the below forum
http://dnsgtforum.forumotion.com/forum

it actually was my forum but i lost the password so i created new forum, but i forgot how to reside to make the right side widget wilder so i can add the chatbox on my new forum like this old forum, i tried to change Pages structure size as well as Modules > Forum Widgets Management > Forum widgets general options, but still doesn't work no matter what side i change to, still doesn't make the widget bigger, would be appreciated if you could help me with this issue thanks

my new forum is PHPBB3