Hello - don't worry she will take a while to get used to you, the cage, the room she's in. All of it is new and she is frightened. Give her time, if she backs away you are too close so take it very gently. Talk to her softly from a distance, no sudden noises if you can help it and no sudden movement. It may be that you will leave the cage door open in a few days time so that she can venture outside and get back in when she wants to. It will be her safe space after a while. Once she has got used to that she may get more curious about you and venture out further.
Don't rush anything, don't even think about a timetable she will do everything when she is ready. Try hard to be more patient than you have ever been while some days you will feel great only to feel as if she has taken 2 steps backwards the following day. Offer treats like sunflower seeds (Syd's favourite) you'll need to discover what your little one likes, but only if she comes to get it from your fingers, or put it where she can see it and let her get it. The best advice I can give you is read as much information and learn learn learn. There are many threads here with loads of guidance and keep asking questions if you are not sure.
I hope that helps until someone with more experience comes along, but it will get you started.