On Windows, the iqdsedit executable is in the %SYBASE%\IQ-15_3\bin32 or %SYBASE%\IQ-15_3\bin64 directories, which is automatically added to your path during installation.
See SQL Anywhere 11.0.1 > SQL Anywhere Server - Database Administration > Replication > Using SQL Anywhere as an Open Server > Configuring Open Servers > Starting DSEdit.