Problems with user files

hi! you need to transfer user files from oncloud 9 to nextcloud 21. if you copy files from a mounted disk, these files and folders are not visible to the user . 2 how to set a different default language for newly created users.please help me

It is always worth to study the administrator guide and use the search function of this forum BEFORE creating new requests for questions which have already been answered several times :wink: