If the living arrangements have not been of her choosing, she might feel very resentful so acknowledge her feelings about that and the wider situation as valid and reasonable. Tell her you know this won't be easy and give her ways to communicate with you that aren't face to face. She may feel more able to let you know what she needs or feels by text or on social media.
In terms of social media, you need rules that keep her safe. With DD1 who is now 18, the rule was that she could have social media accounts but I had to have to password and be able to access them at any time. I didn't assert that right often but I needed to know I could find out what was going on if I was worried. Also she was only allowed to link with or friend people close to her in age who she knew personally or from her school.
Speak to parents of other teens in your area, especially from the same school and find out what social media they are most likely to be using and get familiar with it.
Ask her specifically if there are any family routines or traditions she wants to carry on. Did they always have fish and chips on Fridays, special treats in the school holidays or celebrate birthdays in a particular way?
You might not want to put a tv in her bedroom but it might be nice to give her a DVD player in there and a big pile of cushions on her bed so she can make herself comfortable.
Tell her explicitly what she does and doesn't need to ask for, e.g. she can always just help herself to drinks, fruit, particular snacks but you'd rather she check before cooking a meal.
Show her how to use the washing machine in case she'd rather wash her own clothes and tell her where to put them and when if she'd like you to wash them for her. Maybe you could get the washing powder she's used to in advance. Even your own clothes smelling different must be hard in the early days.
Don't invite people around for a while after she moves in and don't expect her to want to sit and talk to any visitors. If someone does turn up, give her clear permission to say hello then withdraw to her room if she'd prefer to.
Be open and honest with her about needing her to guide you. Tell her you're learning as you go along and that you know you will probably make mistakes but you will learn from them and it will get easier in time.
Good luck.