Na_server database does not exist

Hello, I am trying to open a public database from Fruit Fly Brain Observatory, where the instruction for extracting databases states, “download the compressed database directly and put it in the OrientDB databases folder. You can do queries using NeuroArch Python API”. So I tried to put that downloaded folder called na_server into the …/orientdb-3.0.28/databases/

But when I opened the orientdb console and tried to load the database, it showed:

orientdb {server=plocal:localhost/database/na_server}> connect plocal:localhost/database/na_server admin admin

Connecting to database [plocal:localhost/database/na_server] with user ‘admin’…Exception 0019AAA5 in storage plocal:D:\orientdb-3.0.28\orientdb-3.0.28\bin\localhost\database/na_server: 3.0.28 - Veloce (build b636a4c891bc1b0f93df5bb16ec72dedee7a63e7, branch 3.0.x)
com.orientechnologies.orient.core.exception.OStorageException: Cannot open the storage ‘na_server’ because it does not exist in path: D:\orientdb-3.0.28\orientdb-3.0.28\bin\localhost\database/na_server

Can anyone help me with this problem or tell me why this may happens? Thanks.
The first couples of data files in na_server folder are attached as images.