You will see Progress window whenever WinSCP is performing some operation. Depending on kind of operation it will show various information about its progress.
File box shows name of a file that WinSCP is currently working with.
Progress indicator shows approximately what part of the operation is already complete. The indicator is more accurate when calculation of total transfer size is enabled.
Target box shows target directory of the transfer (local for downloads, remote for uploads).
Time left shows time estimated till operation end. If calculation of total transfer size is disabled, Start time will be shown instead. Time elapsed shows time elapsed since operation started.
Bytes transferred shows total number of bytes transferred in current operation.
CPS shows transfer speed in characters (bytes) per second.
The bottom progress indicator shows what part of the file was already transferred.
Controlling the Operation
Use Cancel button to cancel the operation. Note that with SCP protocol the transfer of file cannot be interrupted without closing whole session.
Use Speed to limit transfer speed. Available only for transfer operation. The limit is in KiB/s. To remove speed limit, set it to "Unlimited". Initial transfer speed can be set as part of transfer settings.