Hi @otuya1,
there is an explanation on how to install the article level metrics (ALM) plugin for OJS 2.4.8 in this thread: Where are the ALM plugin in OJS 2.4.7.1?
But you are using OJS 3 so I think you will not be able to use the ALM plugin as it is not (yet) ported to OJS 3 (see: Database upgrade failed OJS 2.4.8 to 3.0.0 - #11 by asmecher )
Greetings
Hermann