Understanding of a corporate structure is very important to a new employee. Broadly, the management is divided into four categories 
- Top Management: Top management      includes Chairman, Managing Director, Director, CEO (Chief Executive      Officer), CFO (Chief Financial Officer), CTO(Chief Technological Officer).       
 - Senior Management – Senior      Management includes General Manager, Deputy General Manager, Assistant      General Manager 
 - Middle Management – Middle Management      includes – Senior Manager, Manager , Assistant Manager , Officer 
 - Junior Management – Junior Management      includes Sr. Engineer, Engineer, Sr. Executive, Executive, Jr. Engineer,      Assistant Engineer, and Assistant etc. 
 
Typical work experience of these levels if there is not any exceptional case. Most corporate prefers the experience in age as follows:
Top Management generally has the experience of more than 20+ Years. 
Senior Management generally have the experience of 15 ~ 20 years. 
Middle Management people have generally 8~15 years of experience. 
Junior Management has the experience of 0~ 8 years.  
I hope now you able to understand the organizational structure of a company with their age of experience.  But there are many exception in corporate, to recruit the employees in higher position keeping in the mind of their ability and skills.