Agile Development is a human-centered, iterative, step-by-step development method.
Most of us have learned the waterfall development model, it is document driven, why? Because in the entire development process of waterfall, a large number of documents need to be written. After the requirement document is written, developers develop according to the document, and everything is based on the document; while agile development only writes the necessary documents, or Write as few documents as possible. Agile development focuses on face-to-face communication between people, so it emphasizes people as the core.
What is iteration?
As mentioned earlier, agile is a guiding ideology or development method, but it does not clearly tell us what process to use for development, and Scrum and XP are the specific methods of agile development. You can use Scrum or XP. Method; The difference between Scrum and XP is that Scrum focuses on process, while XP focuses on practice, but in practice, the two are applied together. Here I mainly talk about Scrum.
What is Scrum?
And Scrum is such a development process, using this process, you can see the efficient work of your team.
[Three roles in the Scrum development process]
Mainly responsible for determining the function of the product and meeting the required standards, specifying the release date and delivery content of the software, and having the power to accept or reject the work results of the development team.
The process manager (Scrum Master)
is mainly responsible for the development of software products under the Scrum specified process. The number of people is controlled at about 5 to 10. Each member may be responsible for different technical aspects, but each member must have a strong self. Management ability, and at the same time have a certain ability to express; members can use any way of working, as long as they can achieve the goals of the Sprint.
Scrum Flowchart
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What is a Sprint?
1. We first need to determine a Product Backlog (a list of product requirements in priority order), which is the responsibility of the Product Owner;
3. With the Product Backlog list, we need to pass the Sprint Planning Meeting (Sprint Planning Meeting) to learn from it. Select a Story as the goal of this iteration. The time period of this goal is 1 to 4 weeks, and then refine the Story to form a Sprint Backlog;
5. Complete the Sprint selected at the planning meeting by the Scrum Team During the Backlog process, a Daily Scrum Meeting (daily standing meeting) is required, each meeting is controlled for about 15 minutes, everyone must speak, and report to all members what you have accomplished yesterday, and promise all members that you What do you want to accomplish today, and you can also ask questions that cannot be solved at the same time. After everyone answers, they have to go to the blackboard to update their Sprint burn down (Sprint burn down chart);
7. When a Story is completed, that is, Sprint When the Backlog is completed, it means that a Sprint is completed. At this time, we have to conduct a Srpint Review Meeting (demo meeting), also known as a review meeting. Both the product owner and the customer must participate (preferably the boss of the company also participates). Members of a Scrum Team have to demonstrate their completed software products to them (this meeting is very important and must not be cancelled);
the following are some scene diagrams in the development process using Scrum: 
The above picture is an example of a Product Backlog.
The above picture is a daily stand-up meeting. Participants can stand in any posture. The task board must be visible to everyone. When everyone finishes speaking, they must go to the task board to update their burndown chart. 
The task viewing version includes the status of unfinished, in-progress, and completed work. Suppose you have completed an unfinished job today, then you should paste the small card from the unfinished area to the completed area.
Everyone's work progress and completion status are open to the public. If a person's work tasks are placed in a certain position for several days, everyone can find out what is wrong with his work progress (the number of members is preferably 5~7 so that each person can use a special color label, and at a glance from the task board, you can see who is progressing fast and who is slow.)
The picture above is not a playing card, it is a planning card, and its role is to prevent the project from being led by someone during the development process.
How is it used? For example, it takes 5 hours for programmer A to develop a function, and programmer B thinks it only takes half an hour, then they each take the corresponding cards, hide them in their hands, and finally showdown. If the time gap is large, then A and B can discuss A Why 5 Hours...
A 4 Sentence Manifesto of Agile Development
Software that works is better than comprehensive documentation
Responding to change is better than following a plan