Hello Julie and welcome to our family, so glad you are joining the ranks of grey ownership, it is a decision you won't soon forget.
You want to bring Louie into your home and allow him to settle into it and go at his own pace as it will all be new to him and he may be a little frigntened to be bombarded with all new things, new home, new cage and such. Don't force a relationship and allow him to come out of his cage on his own and he will let you know when he wants more interaction. He will know there is another bird in the house and you can introduce them but don't let them get to close to one another as they may not get along, greys are notorious for shunning other parrots and even another grey.
If you are putting him into the cage he will be calling his home and he is still a little clumsy you can put his perches down a little lower in his cage and put some towels or blankets down to cushion any falls until he gets more steady, be sure to cover the soft cushion with newspapers so it doesn't get so dirty with poops.
You will find lots of useful information in our many threads so do read thru them at your leisure and ask any questions you may have and we will help you in any way we can.
If you have any pictures of Louie you would share with us we would love to see them and we have an amazon room where you can put some of Tarzie, I assume that is your amazon.