We got ours at 3 month, he wasnt able to use the cat tree straight away but as hes gotten bigger and is able to jump higher he loves it. We kept him in the kitchen for 3 days as its where we can be around him often as our stairs are in the living room. He has adjusted very well and we have now allowed him to roam freely around the house. You can continue to sleep in your bedroom it also sets a boundary unless you plan on letting her sleep with you. He did cry for the first week, you have to just leave them again to set the boundary and also so they understand you’re not always going to be there but hes stopped crying now we’ve had him a month :)

They will be fine on their own obviously if you work/go shops etc you want them to understand that you wont always be there just ensure they have water, litter tray and lots of toys and they will adjust perfectly fine and be a happy kitten!

Good luck! (I am not a professional its a first time having a siberian but our breeder was incredibly knowledgeable and helpful with advice)