https://lemm.ee/post/65824884 for details.
Moderators interested in migrating to a new community on another instance might want to consider selecting an instance and doing so sooner rather than later so that users here have time to see a migration post here and subscribe to the new community.
The easiest method of transferring existing posts to a new instance is by migrating to a Piefed instance, which has a unique ability to create a backup of all previous content from a lemmy community.
One limitation is that the backed up previous content is only able to be seen from the piefed instance itself, it cannot be seen from outside lemmy instances (though people would still be able to go to this lemm.ee community from any other instance that was federated with it, as it will retain a local copy as well).
To create a new copy of the contents to another lemmy instance, I believe you would have to involve the use of an automated bot.