What is the purpose going agile ?
We embrace Change !
In contradiction to classic software project management changes are accepted during the agile software development.
This means that between waterfall or V-Modell and Agile Project Management there are many differences. Not only for the team who is developing the software but also for other parts of the software house and the customer the software house is working for.
The customer can be another department within a company. It can also be another company which orders the software.
If the software house creates potential shippable increments during a short iteration and asks for feedback at the end of the iteration the customer has to follow the progress in a similar velocity. In consequence it enables the customer to react much faster to changes in his market. As a result the customer could be one step faster than its competitors.
But not for nothing: he is asked to give feedback after every iteration and this leads to closer connection to the software house (supplier).
It's no self purpose.
There is nobody in the team who knows all. Therefore the team members need to collaborate. Sharing knowledge with others works only in an atmosphere of trust.
Inspect & adapt
Requirements are changing leading to user stories which change. After every iteration this needs to be inspected. Prioritizing user stories after every iteration is adapting to the changing requirements.
This is important and one essential mechanism doing agile.
The teams reflects how it was working during the last iteration. The team members think about what was good and what needs to be improved.
This is done during the retrospective. There are many different ways to execute a retrospective.
The Scrum Master needs to have a collection of retrospective exercises for different purposes and goal of a retrospective.