Congratulations on the first step of the process - Landing in Germany. Its good that you have a clear long term goal : German PR and a German career.
The start of this journey is the absolute right time for you to setup the right foundation for your career.
To achieve this goal, you need to break it down into smarter small term goals:
Ace your course : make sure that you are laser focused on the course/domain that you are in. Keep you head down and focus on learning the fundamentals and application of the subjects. If you are lacking on those, you will struggle with the next step
Getting a well paying job : delivering food and groceries is a job which earns you €10-€12 per hour. Getting a well paid internship is better. Getting a job that pays €70,000 is always better than getting a job that pays €45,000.
High paying jobs are possible
You need to be much better than the competition to get that high paying job
You job prospects will entirely depend on the knowledge of your domain and
what real value you can contribute to the company in a role
Learn German language : one of the most over-looked yet important aspects. Getting a job might be easy, going from a €50,000 to €100,000 job is a different thing. You will need to be part of the work force, adapt their :
working style
culture
behaviour, and
language
Build a network : One of the most common mistake Indian students do is stick around with Indians. There is nothing wrong in that. Being in Germany, your social circle should include Germans, Swiss, Spanish, French, Italians, Americans, Australians, Canadians also.
Network DOES NOT mean asking a job or references only
Once you complete the required time, 21 months if you have a Blue card, you can apply for a German PR. This is a formality since its just filing application n documents, there is no subjectivity if you get it or not.
You can find a detailed post on my German PR process here : Link