Simply put, it is an automation application available only for the Android OS. It is arguably the most powerful app available in the play store. Most avid Tasker users, such as myself, swear by it. All programming experience levels can use Tasker. From people with no programming experience to expert script writers; it can be useful to all.
For Example: if you just want to automate when your Wifi or Bluetooth connections turn on/off, Tasker can do it. If you want to receive a notification, only when you are at home, that when clicked opens a dialog with your YouTube Watch Later Playlist Videos which are ready to cast to your TV, it can do that too. Of course the latter will require the use of a few plugin extensions and YouTube API calls, but the point is that a person with any level of programming knowledge can use this application to suit their needs.
Until I update this post with my own beginner’s tutorial post, here are some links to get you started: