Decorating a new home is challenging because there are no guidance and no rules as which room is to be turned into a bedroom and which one is living room. You would be placing the furniture items and accessories for the first time in the rooms as well. I suggest you to do the following:
Make a nice map of everything and create a layout on your computer.
Make a to do list. And do one task at one time everyday to do the decor nicely.
Keep the track of the things or tasks you have done.
If you have not been able to purchase new furniture items for the living room or the other rooms, you can definitely arrange the old furniture and then replace it with the new one once you have time.