My two arrived with me ages 4 and 6, and to be honest I’d go against some of the advice from previous posters. We got furniture for the kids rooms and freshly painted and carpeted them, we also got lots of storage for the playroom but didn’t buy toys or clothes until we saw what was coming home with them. There was lots of stuff some of it meaningful to them - including toys they had really grown out of but which were familiar.
I didn’t plan their rooms with them during intros - intros were incredibly stressful and both kids were scared and overwhelmed. We used intros to get to know them a little bit and try to help them self soothe.
In terms of their bedrooms, it has taken them a long time to take ownership of their space - they didn’t move toys into their rooms for about 6 months, still don’t like pictures and posters on their walls and my DD(7) has only now asked for a rug for her room. I’d take it at their pace, which may be quite slow really.
In terms with of what to expect, really listen to the information given to you at the various meetings, but also think about how you want things to be at home. By way of example, my DS had a terrible sleep pattern in foster care - one of the first things we did was work to regulate his sleep which made a huge difference to him emotionally. Pick one or two things to set boundaries around (for me I focussed on safety and well-being, hence sleeping), don’t be afraid to set boundaries - my two really need to know where the lines are to feel safe.
Work on attachment - my DC were glued to me for months, not just a bit clingy, I mean they wouldn’t let me out of their sight or touch. Go with it, recognise all behaviour as being communication - challenging behaviour at this stage is about distress so always come from a calming place (make sure you have places you can scream though). Don’t take anything personally - one of mine was very rejecting of me and the other had very split loyalties, you need to roll with the punches a bit. Which brings me to the next bit.
I put them in school and nursery after about 8 weeks, which goes against all accepted mn/adoption wisdom re attachment. They really needed the familiar routine and I really needed physical and emotional space. It helped me be available for them outside of school. Their school is fabulous and has helped them feel settled and accepted. There were no expectations at all in terms of behaviour or learning, the aim of that first year for my DD was simply to get her to a place where she liked school, and for my DS to gain some social skills. So, no pressure whatsoever and even now, a year on the school and I agree that academics are less of a priority for now.
While they went to school/nursery, I didn’t do any out of school activities (dancing, rainbows etc) for the first year, they now both have one activity they both do at the same time which gives my DH and I time to have coffee together - invaluable.
I also quite quickly (ie in the first month) introduced them to two extended family members who I knew would be involved in supporting my DH and I. It meant they had a relationship with someone close that we could leave them with for their court hearing!
Expect the first few months to be harder than you’d imagine, it gets much better - I couldn’t be happier now - but oh my goodness it was hard at the start.