They will be two separate titles. If you drag them both to the main menu page then you'll get two buttons, one for each video. Both of them will begin at 0:00:00, each on their own individual timelines. You can add an end action for the first video to link it to automatically play the second one when it's done. That way your viewers can opt to start at the second on if they wish, or if they start with the first they'll see both.

You can also create a music compilation that will allow you to load both videos together and treat them as one continuous item.