I'm usually the third person in a team, along with two qualified linespeople, but I've worked with lots of different people during my apprenticeship. I've got to know a lot of the people in my local area already.
Some have years and years of experience and know everything there is to know about the job. Others finished their apprenticeship just a couple of years ago.
If I ever wonder whether I should already know something, I ask them, and they'll tell me they felt the same way. That's reassuring, and that's what it's all about – learning the job and getting to know people at the same time.