so i download the app and when i try to open it the thing wont open it just says this application can not be ope
You might need to right click (or ctrl-click) and then select "Open" to get around Mac security settings. Unless you code sign your application you may need to also disable Gatekeeper by setting System Preferences -> Security & Privacy -> Allow apps downloaded from "Anywhere"
I highly recommend turning that back on after you start your application if you do end up needing to allow apps downloaded from "Anywhere"