DevOps tends to break down across three major dimensions:
DevOps culture emphasizes high levels of trust, collaboration and communication between all stakeholders, especially Dev, Ops, and Security. The natural tension and competition between these groups creates friction, and often dysfunction. DevOps is (arguably) first and foremost about aligning efforts between these teams.
DevOps development processes align closely to Agile processes. Ops is encouraged to take up Agile-like practices to better align to Dev efforts. DevOps-aligned processes are designed to support high velocity and fast feedback loops throughout the development/delivery lifecycles. Continuous Integration, Continuous Delivery, and Continuous Improvement (kaizen) are focus areas of DevOps process.
DevOps isn't a tool, but it is supported by tools. There are whole families of tools supporting a range of areas including Continuous Integration, Source Control, and Application Lifecycle Management.
A "DevOps Transformation" must address elements of all three, but not necessarily all equally at the same time. There is a natural progression and "critical path" for transformation. The argument could be made, for example, DevOps is dependent on some form of Agile practice, at least within the Development team/teams. Issues with culture may need to be addressed before investment is made in tooling.