Click where is says "Download Now" and it will bring you to the main page (where you probably should be commenting and asking questions and stuff), click the link that fits your computer, extract the files, take the folder with all the game files out onto your desktop, open that, and look for the Clangen.exe program. Once you run that there might be a warning but just click "Show more" and then "Run anyway" and then it should be all good.
Hopefully I am thinking of what your problem is, but what I'm thinking is that the Microsoft Windows thing is some sort of virus scanner that thinks the file is a virus or something like that, even though it's not. I've only dealt with two virus scanners, one was a red box that says something about how the program isn't safe, in which case do the warning thing I said. But I think it's a built in virus scanner. Try click the search bar in the toolbar and type in "virus" and click "Virus & threat protection." After that, look under the part that says "Virus & threat protection settings" and click "Manage settings." Then turn off the real-time protection and quickly try to open the clangen.exe file. If you're not quick enough then the virus protection will turn back on again.
Sorry this is so long, I just wanna be specific. If you're still having problems then you should try asking again on the main page or the discord, you'll find more experienced people there, hope this helps! :]