The install files presented here are compiled to windows and traditionally only need a double click to start the installation process,
Thus, you only need download it from here . All the install files in the directory have a filename with the name structure speckleonline_X.Y.Z_ARCH_install.exe, where X.Y.Z is the version, and ARCH is the architecture, typically this value is i386 or amd64, to 32 or 64 bits architectures respectively.
To execute the speckleonline program you need go to installation directory and do double click in the bin/speckleonline.exe file.