Life Cycle Rule to move a subfolder of S3 Bucket

S3 is an object store. Every object in S3 has a unique key which comprises the bucket name, the prefix hierarchy and the object name. So there isn't really a folder structure like in a file system in S3. The prefix hierarchy may make it feel like you actually have files organized into folders. On the UI, you do see folders but those folders actually map to prefixes. So to answer your question, you don't need to map prefixes to folders.