Can't open app

[Plarson18]

I am trying to download, open, and ultimately use the application, but after I download and go to open it, it says the developer can't be identified and I am completely unable to open the app. I am prompted with two options when I try to open it. First is to move the file straight to the trash, and the second is to cancel which just closes the window. I am completely unable to open and use Onetagger :(

[bascurtiz]

Maybe this helps: https://youtu.be/8IDG0igqJQs (macOS) or this: https://youtu.be/JBE61pq5i8o (Windows)

[Marekkon5]

Video has solution to this problem, inactive issue, closing.