I am a complete novice to 3D printing and need help to find where I am going wrong.Installed Cura 15.4.6 on a Windows machine.It starts and appears to be running ok.The printer settings were changed to what I think they should be.However when I load a stl file Cura will not slice the file.Could somebody please help me where I am going wrong and steer me in the right direction to fix the problem.