After downloading the dynadocx package, be it a trial version or a paid one from the dashboard, you have to extract it with a decompression tool for ZIP files such as WinZIP, WinRAR, 7-ZIP, unzip, or any other.
Once the files are unzipped you can start working with dynadocx.
To execute dynadocx it is required to assign execution permissions to the bin/dynadocx file. However, if you want to execute it from anywhere without a reference to the absolute path it is advisable to add it to a directory of the PATH of the operating system.
By default, macOS does not allow working with apps from third parties, not downloaded from the Apple App Store or non-verified developers, unless stated otherwise on the preferences. macOS shows an alert regarding this when attempting the task.
Given that case, to work with the dynadocx package it is necessary to grant it permission. Go to System Preferences > Security and privacy > Allow apps downloaded from to allow macOs to access the package. You can set back the security permissions after installing it succesfully.