Upper right side of the post. Shows a date after so many days (not sure how many). Otherwise its in minutes, hours, or days since the post was made. Your's said 8h when I posted this.
Easiest way to start a new thread/question would be to determine which subject you want first. Suppose I wanted to start a thread on how BYU Football will do this year. I would first go to the Main Page. I would then select the category 'Football' . At the top right hand side, there is a button called '+ New Topic'. Press that and you have two entries, the subject, and the content.