Reversing Posts

Okay..
First time using WordPress, and I thought something like this should be a matter of a tick box.. Apparently not..

I’m trying to host an educational video based website
Videos hosted through VideoPress, Self hosted WordPress on my own VPS. The problem I have is getting the posts in reverse order so 1,2,3 not 3,2,1.

Since the videos go from easiest to hardest with new additions being harder it makes sense to have posts in reverse for noobs that come on to my site.

I’m currently using the Tonic Theme by Bavotasan.

I don’t know the exact PHP file to edit to change this..
Other posts seem to be related to older versions of WordPress.

Thanks!

Matt.