Hi Suvetha,

You have to put the file (the .gha) here: C:\Users\<YOUR USER NAME>\AppData\Roaming\Grasshopper\Libraries

Also, right click the .gha and make sure it's not blocked (under the general tab at the bottom)

P.S. Rhino 6 comes with Grasshopper and Kangaroo. It doesn't appear for you in Grasshopper?

Best,

Arie