This is the 896th most frequent Chinese word.
有序
Orderly; organized.
有序 in this sentence describes the adjective (orderly) characterizing the implementation of their plan.
他们的计划进行得非常有序。
Their plan is proceeding in an orderly manner.
Here, 有序 acts as a modifier for 分工, indicating tasks need to be organized in an orderly manner for efficient cooperation.
为了成功合作,我们需要有序分工。
For successful collaboration, we need orderly division of tasks.
In this usage, 有序地 serves as an adverb, qualifying the verb 排列 to express that items are arranged in an orderly fashion.