The third step is the design of the message. The designing of the message follows the objective of the message. The design of the message has to address the following four points, content of message, message structure, message format and message source.
The fourth step is the selection of the communication channel. The channel must be appropriate to carry the message to the target audience. For pharmaceutical companies, their sales people are the most effective channel in reaching the target doctor audience, instead of placing billboards.