Here is a book recommendation for you!
I Love You Rituals by Becky Bailey is not specifically written for adoptive families, but can serve as a wonderful resource for attachment activities that are natural and easy to start doing in your home and with your family. This can be of great help early on after your children have arrived home. Attachment activities can help build strong bonds between parents and children as well as siblings and grandparents.
It is available in bookstores and also on Amazon!