What you can learn from doing these things depends on what you want to learn from them. For example, if you want to learn business administration, you can learn it because you are facing a real business administration case.
2. The salary level is average, similar to that of an administrative clerk. Newcomers are like this. As for the specific treatment, it depends on the company. Every company is different, and there is no generalization, because every company has different ways to evaluate employees' salary. Some depend on how many cases you have participated in, while others depend on how many clients you have won.
3. Generally, there is induction training. If not, there is no good way to adapt to work. Only pay more time and energy to try to understand this line, try to understand the company's situation, and analyze every customer information sent to you, as well as the cases that the company has done before. That's all.