All you need to know to play it is mathematical addition with numbers up to 14. In essence, just sum the cards on the table and take them with your card. But if you are able to remember past cards and think in advance you can get it to very high level.
Tablic Masters is online interactive game so you compete with other people logged in from their phones and computers. It is also available on Facebook under the same name. You can login to Tablic with your Facebook account either from the computer or your Android device or you can play as Guest.
If you login with Facebook account, you can take over the game from one device to another without loosing time and points. Facebook login also gives you free daily chips for playing.