Clear the storage, remove most of the apps and take as many icons off the desktop as possible if it’s a PC or Mac. All extraneous manufacturer on-screen docks and toolbars should be deleted. Now install Skype, whether that’s on a PC, Mac, iPad, iPhone or Android phone. You’ll then need to set up a Microsoft account if they don’t have one. If they have an Outlook.com (formerly Hotmail) or similar they already have a Microsoft account. Tick the box to start up Skype as soon as the computer logs on. Add your contacts - get all the family added, making sure that they accept the requests at the other end. If you’re setting it up for someone else, tell them to vet friend requests. Check that the call, video and microphone settings work. Then head to the Privacy area and make sure that no one other than known contacts can call, video call or IM.