are they the same?
【Remain a free agent as long as you need to.
When you walk into an organization, the formal hierarchy may seem clear, but it takes time to learn how things really work. Who get things done? Who are the power players? They may not be the same people. What are your goals, and who will foster them? Be friendly with as many people as possible. Try not to be thought of as belonging to one clique or another. Think of your early weeks and months as a B-school assignment. Map the organization to gain a deep understanding about the people and the place and who is most likely to advance your objectives. Advantages don’t always come from the most obvious sources. Take time to search them out.】

in this context, does "get things done"= "finish the work"(which indicate to workers), does "the power players"=executives? then, what does "they may not be the same people"mean? they are different in the first place, aren't they? or does "who get things done" also indicate to "executives?"

Question

are they the same?
【Remain a free agent as long as you need to.
When you walk into an organization, the formal hierarchy may seem clear, but it takes time to learn how things really work. Who get things done? Who are the power players? They may not be the same people. What are your goals, and who will foster them? Be friendly with as many people as possible. Try not to be thought of as belonging to one clique or another. Think of your early weeks and months as a B-school assignment. Map the organization to gain a deep understanding about the people and the place and who is most likely to advance your objectives. Advantages don’t always come from the most obvious sources. Take time to search them out.】

in this context, does "get things done"= "finish the work"(which indicate to workers), does "the power players"=executives? then, what does "they may not be the same people"mean? they are different in the first place, aren't they? or does "who get things done" also indicate to "executives?"

Answer

Those who "get things done" represent employees who have established excellent working relationships within the workplace. They are able to facilitate and streamline processes and make the job easier. 
The "power players" are those who wield effectiveness regardless of their position in the organization. For example, at a newspaper publishing job, one of the supervisors in the editor's office is able to prioritize the shop's project schedule, so this person, although not an executive, has the position power to help one get their work completed early, for example.