By default, timestamps displayed to you on the forum will be in the "Month/Day/Year" format, with a 12-hour clock (AM/PM). However, there are a couple of different options available to you to allow you to change the format for timestamps depending on what you are more accustomed to.
To change the way timestamps are displayed to you, click the Profile button found in the top menu bar of the forum, then on your profile page click the Edit Profile button. You'll then be taken to the Edit Profile & Settings page; once here, look for the Dates and Times option found at the very bottom of the page.
You'll see a couple of different drop-down menus available here. The first drop-down menu will allow you to change from the Month/Day/Year format to display as Day/Month/Year instead. The second drop-down menu allows you to choose to view times on the forum in 24-hour time, rather than the AM/PM system.
Make your selections, and when completed, click the Save Account Settings button. Once this is done, timestamps on the forum will be displayed in the format you have chosen.