Unfortunately, it will NOT be this easy. Those with just a basic understanding of how the insurance process works knows it will take time to roll it back, unless, of course, you want single payer. It will NOT be an easy process, despite armchair pundit's claims to the contrary.
1. The original law passed by Congress.
2. The executive orders and HHS regulations that were imposed since the original law, which exercise authority that is given to the executive branch under the original law.
Trump cannot overturn the original law on his own, but he can go a long way toward "fixing" the problem by rescinding many of the things that were imposed under Item #2.
Trump can also immediately cease and desist in any enforcement activity or court proceedings involving compliance with ObamaCare provisions that were left solely to the discretion of the Secretary of Health and Human Services, for example.