First you need a VM, which was backuped at least for one time. On this VM you can open an explorer with https://'IP-of_your_VDP-appliance':8543/flr/
Than you click on "Advanced Login"
Local credentials: A user which has access to this VM
vCenter Credentials: Only this user, which you have used to configure your VDP with /vdp-configure. (Onother user does not work)
After the Login you can restore files from all VMs of your Backup-Store to this VM.
If you use Internet-Explorer and only see a blue screen, than you can try to click on the "Compatibility view" button.
For File Level Restore under Linux you need a Linux-VM with an explorer.
There is a limit of max. 5000 files per restore.
Paul