How do you get involved in a new project?

Question

Work organization

I got a job as a junior in the development department, I will be involved in 2 projects.
Unfortunately, it is rather weak with documents, there is not much legacy code, there are no tests.
For a week, I more or less entered the work process, solved several combat missions and even refactored a couple of hefty controllers. Made a couple of manuals for deploying projects locally.
Questions to the masses:

• how do you enter projects?
  
• how do you accept and draw in newcomers?
  
• how do employees go to refactoring a newbie's code in a working environment?
  
• do you immediately start covering the code with tests as you go?
  

Answer 1

To quickly start working on a task, an employee who has just joined the project needs the following things:
1. Centralized structured project documentation for the entire solution being developed.
2. The architectural scheme of the solution and the marked block in which the task will need to be performed.
3. A brief description of the task and a method for checking its complete implementation.
4. A brief architecture of the code of this block and an indication of the place with an explanation to start the work.
5. An indicative list of the most likely names of classes / methods / related APIs to be used when completing the task with a brief description and links to the centralized documentation (clause 1).
6. An indicative list of classes/methods/related APIs thatmay be needed (as well as in paragraph 4 with links in paragraph 1).
7. Recommended development environment for the task and its settings for this task
8. Estimated task completion time
9. Contact with other developers (indicating their areas of responsibility in the project and availability time) for emerging questions regarding this task.
Ask for a task in this format: for someone who has been working on the project for a long time, it will take no more than an hour, and it will save - weeks of project development!

Answer 2

2 weeks to more or less adequately navigate there and be already unconditionally useful for the project.

Answer 3

Oh, hi, Maxim.
In fact, if there are no docks, no tests, etc.
Then you have only one option: just read the code to the maximum and try to ensure that your newly introduced logic does not break anything locally. And then you will enter the project and you will feel more confident.
But the code must be read anyway, and the more the better)