Study and understand your business needs before considering what systems are needed as far as hardware, operating systems, and applications. Once the business needs are defined and understood, search for the best applications, hardware, and operating systems to meet those needs. Develop an installation and implementaton plan.
Study and understand your business network needs. Once the business network needs are defined and understood, determine the best network topology (wired and wireless), choose network components that meet the network needs including management and control of network infrastructure.