It's actually quite simple. Interns are no different from children entering the company. The company will arrange a week's training first, and then go to the office after the training. According to different work arrangements, some interns are in the office, some may work on projects and may need to go out on business trips. There are fewer projects in summer internship than in winter internship, so it is not expected to be very busy.
For interns in the office, they may need to help many senior colleagues, and the things they need to do are complex and basic, such as printing and copying, checking Chinese and English statements, filling out and sending confirmation letters, checking excel numbers, checking statements, and searching online. If you want to travel on field, the project will be more specific, but everything you do is similar.
On the second question:
If you want to stay, please ensure a good attitude, be responsible for your work and be sincere to others. In fact, no matter how trivial and unskilled things are, you can learn something, including work style and attitude. Even the smallest thing can show your ability. As long as it is done, you can basically get the par surface, and it is easy to stay.