If you have powershell installed on the system where you install the DST tool you will typically have a "Directory Synchronization PowerShell" available in the Start Menu for DST.

There are a few reasons this may not be available or may not be working properly if it is available:

If it is not available typically it is because the prerequisites were not available on the system during the install which means you need to go install Powershell and reinstall the DST in order for it to appear.

Also there seem to be issues more so on 2008 R2 systems where UAC is enabled that the installer does not elevate which is required for the powershell component.  To overcome this issue open an administrative command prompt by right-clicking command prompt > Run As Administrator and then change directories to the location where the DST setup exe resides and rerun the setup for the DST again.

Although it does not state so on the DST download page, the DST Powershell environment does work properly in Powershell 2.0.