You may need to configure a staging server using Veeam Explorer Options - in particular, to restore database to the state before selected transaction. In this case, you will have to specify the user account for staging server access. You can either use current user account (under which Veeam Explorer is running) or specify another one.
User account should have local Administrator rights on the specified machine, as it will be used to access administrative shares, and sysdba rights on target server. If you plan to use Oracle 12c as a staging system, you may also need to enter a password to access Oracle Home on that machine. The Logon as Service right must be granted to the Home user.
This should be a root account or account elevated to root and added to sudoers - for that, click Advanced and select the corresponding options; if necessary, enter Root password and click OK to save the settings and close the dialog. This account should also be a member of dba and, if necessary, of asmadmin group for the Oracle server.
When elevating account to root and adding it to sudoers, current settings will be used by default (in particular, root password). Consider that if account privileges should be recalled after backup/restore process, you will need to do it manually.