Recovery of a broken backup file MS SQL 2012

Question

SQL

Good afternoon.
The trouble happened like this:
The server crashed, as a result of which the MS SQL 2012 database, on which the application was running, fell.
But there are full backups of this database. The problem is that they are on ftp. And at attempt of recovery SQL writes that the data set is not selected.
It turned out that the transfer of databases to FTP was incorrectly configured.
But I can't find anywhere how to restore a broken database.
Help me please!

Answer 1

1. What about the base that fell?
2. Is the file downloaded from FTP?
3. What is it called (extension)?
4. Do you have SQL server access rights to this file?
5. Exact sql error?

Answer 2

1. The database was restored from a very old copy.
2. Downloading.
3. *.bak
4. What rights does SQL server need for this file? And how to give them?
5. In the recovery window, selecting the device-file-file_backup, it is written at the top - no data set has been selected. Accordingly, it is not even possible to restore.