You may need to mark the mark the program as executable. Depending on your Linux distro, you may be able to do this by right-clicking on the file `Digital-Logic-Sim.x86_64`, selecting Properties, clicking the Permissions tab, and ticking "Allow executing file as program".
Alternatively you can open a terminal in the Digital-Logic-Sim folder, and run the command:
sudo chmod +x Digital-Logic-Sim.x86_64
You should then be able to launch it by double-clicking the Digital-Logic-Sim.x86_64 file.