Unable to attached ( .Dgnlib ) file to my system Bentley Microstation

Hi Sir 

I am Sachin Kumar. I am using Bentley Microstation V8i ( SELECT series 10). One of my friend in my organization created a (.Dgnlib ) Library file for ( Metallurgy Levels, Equipment Boxes, Multilevel Colors ) for P&IDs Drawing. He shared that file to use for everyone. But, I am not able to attach that file in my system folder. He asked me to place that file in my system at the following path 

C:\Program Files (x86)\Bentley\MicroStation V8i (SELECTseries)\MicroStation\mdlsys\required

Can You please help to resolve this issue. How can i attach that library file to my machine to use in Microstation work 

Regards

Sachin Kumar 

Anonymous