The SWNetwork.unitypackage can be found on the https://www.socketweaver.com/download.html page
Installing the package is simple using Unity Editor.
1: Select Assets->Import Package->Custom Package..
2: Choose SWNetwork.unitypackage in your local file system.
3: Select all the items in the Import Unity Package window and click Import
4: SWNetwork libraries will be installed under the SWNetwork directory in you project.