Please tell me about the training when you first joined?

For official training, you'll be assigned some training videos that go over company policies and procedures. I don't remember exactly how many of these there were, but if I had to estimate, there's about 10 hours of videos total (so about 1 hour per day for your first two weeks). There's also a new employee orientation held virtually about once every two weeks, so you will be invited to the first session after your start date. As for your specific job function, it's really up to your manager how you will be trained. In my experience, I was added to some smaller projects right out the gate and learned by doing! I'm sure other teams have more formal training depending on the role. You will have contacts both on your team and in HR to ask questions about either your job role or company logistics (things like payroll, PTO, benefits, etc.) as you adjust to your new job.
Additionally, for new college grads, we have a program called NextGen that organizes lunch and learns and networking events to help new employees integrate into life at Nokia. Recently, NextGen has launched the "Hackweek" program, which is a week-long virtual event for new hires from across the world. Through Hackweek, you'll get a taste of our mentoring and coaching programs, get to learn about building your own personal Nokia brand, learn about our wellness and inclusion initiatives, and much more!