It's ok, they should expect that you on the learning curve

Try to make good relationships within your team. Ask for some helps when you need to, sometime you really need to figure it out by yourself. Be careful to ask too many basic questions.
Find some documents to get familiar with the terms and things you are going to do. You can find that info on the documents from your boss or/and your team members.

with "Can-do" attitude, even though you do not know at this moment, and try to be confident. "If you don't trust yourself, why should I?"
Good luck.