Now that the CreateSpace team has begun reaching out to authors about migrating their books from that platform to KDP Print, we've learned that CreateSpace prefers that authors wait until they contact them to do the work. CreateSpace is not prepared for all works to be transferred at the same time. Instead, they are setting up the process and will reach out to authors as they have prepared the way for those works to be transferred.
If you haven't yet received an email message from the CreateSpace/KDP team, be patient. Those who have heard from CreateSpace and have followed their recommendations have reported positively on the process.