For transferring files to PV Log.com, the freeware program FileZilla is a good option. After starting the program you will need to enter ftp connection information in the top line. You find this information (after logging into PV-Log) in "My Profile" -> "Automatic data import / data logger". After selecting "SMA" for Manufacturer, "Sunny Explorer" for model and "FTP" for Transmission Type, the details you need will appear.
Subsequently in the left column you chose the folder that contains the CSV data on the computer.
Now the files from the computer are being synchronized with the data on PV-Log:
You should now see the left and right column being filled with the same files. So the data is now available to PV-Log and will be visible soon.