"Is there a roadmap/guideline for that?"

The difficulty of the migration depends on the complexity of ICT infrastructure that needs to be migrated. Basically, a company does not need to know how to deal with the migration, but it should acknowledge the need for a roadmap and know where to look for it. The first step in IPv6 migration is not the migration itself but the decision to start making a roadmap for the migration. A company may choose to either educate their own people or hire external architects and engineers. It is expected that over time migration will become easier.