Re: Willow has arrived .. and i have no idea what i am doing!
probably keep her in that room for the first few day until she starts to feel more secure there, before letting her leave the room. Make sure shes got a safe comfy spot under the bed that she can always run to. Move slowly and quietly and speak to her gently. Yawn and sigh relaxedly as signs cats can relate to. let her smell you before touching her. Make yourself her height when trying to make contact. Stop touching her when she warns you and give her space.
Edit: wait - dont you know all this already?