...
Clean Up Content
As your ArcGIS Organization ages, it is likely that you will have broken, out of date, or unused content. Content that has broken links or other errors will not clone successfully. Depreciated or unused content will just take up extra space in your organization. We always recommend cleaning up the content in your ArcGIS Organization before starting a cloning operation. To support this process, we have created Clean My Org.
...
If there isn’t a match, BMO will suggest you create a new user in the target Org with that user’s information.
If it does find a match, BMO will suggest you restore the user from the source Org to that user. If you do so, the user in the target Org will have their information overwritten with the information from the user in the source Org. If you do not want to do this, we recommend you create a new user instead (you will be prompted to provide an alternative username for the new user).
Clone Groups
After you have finished cloning the users, you may begin cloning the groups. At this time, we do not have any recommended special considerations for cloning groups.
Clone Items
We highly recommend cloning items in batches based on the item type. By breaking the cloning part into segments this way, you ensure that any supporting content (like a web map) has been cloned before something that needs them (like an application). This also gives you the opportunity to identify any hiccups in the cloning process and address them before they become more complicated.
...
NOTE: while there is a notable variety of item types, they are not all supported for cloning in Backup My Org. This may be because the REST API currently doesn’t share enough information for the item to be cloned successfully, because the Products team is still developing and testing the workflow, or a variety of other reasons. If you would like to double check the list of unsupported item types, you may do so here. If there is an item type you specifically need help with, reach out and we will see what we can do.
Clone Groups
After you have finished cloning the users and items, you may begin cloning the groups. At this time, we do not have any recommended special considerations.
Testing
Test to make sure content is working properly in the new environment.