Currently, there is no automatic migration tool. Our Launch team is currently working on the migration tool that will automatically migrate the vast majority of your DTM items across to Launch. If you'd like it migrate before this tool is ready, you would need to recreate each of your web properties, rules, data elements, and tools.
With that said, some customers may benefit more from a complete rebuild as it gives you the opportunity to follow best practices and remove rules and custom code that was used as work arounds to the limitations of DTM that are no longer present in Launch ( clearing variables and aborting the default beacon just to name a few).
Thanks,
Jantzen