If you don't know who Nia is, you most likely need to continue Lin's storyline.
Thats what im trying, and when i click on the door, it says i need to speak to nia
*/MAY CONTAIN SPOILERS*/
Either you haven't yet encountered Nia (Progress with Lin), you need to build the Sanctuary (See Ellen), you need to purchase Nia (Your computer), or you just need to go to the Sanctuary and interact with Nia (Front Door).
Hopefully that helps.
Thank you for that, i have built the sanctuary, so maybe its one of the other ones, thanks again
