If you have the necessary knowledge to perform an attach or detach content database move, here's the link that will show you how to do it: http://technet.microsoft.com/en-us/library/ee947141(v=office.15).aspx
However this method can be time consuming (temporary farm creation etc.) and has its limitations such as broken links, broken workflows... Using a third party tool is usually the preferred method. There are many tools on the market. I recommend you to test their free trials to know which one suits your needs. Also, don't be afraid to ask them questions so you can have an idea of the support experience.
Stephanie from Share-gate