Communication includes documentation using templates describing the solution in a understandable and correct way.
The documentation has to be maintainable, clear and adequate depending on the complexity of the solution.
Use google for more information
This diagram has been developed based on several books and also by many years of experience in software engineering. You may use the links and book recommendations on that page to get more information to specific parts of that big picture. The used six main categories have been adpopted from Gernot Starke's book "Effektive Softwarearchitekturen". The big picture diagram is also a good resource for preparing the iSAQB certification test.