How to merge clips in the right order?

Hi everybody,

I'm just starting to use Hitfilm Express for the first time. It seems pretty easy, except the fact that I don't understand why it can't put the clips I gave him in the right order.

I have to merge something like 250 clips in one big video. The names of the clips are numbers, like 1, 2, 3..etc (made by Windows) and when I import them, I have them in the right order. But when I put them in the timeline, they get all mixed up, like 1, then 10, then 100, then's a very pain in the...

Is there a way to keep the order? Or do I have to order them manually one by one? I have thousand of clips to do...

Thank you in advance