$ sudo apt-get update
$ sudo apt-get install libgtk3-perl 

libgtk3-perl is installed in your system.

Make ensure the libgtk3-perl package were installed using the commands given below,

$ sudo dpkg-query -l | grep libgtk3-perl *

You will get with libgtk3-perl package name, version, architecture and description in a table

libgtk3-perl package basic information: