Video slots are a nicer representation of the old-fashioned slot machines that used to be in pubs and snack bars and still line the walls in most gaming halls. A video slot is a digital version. Instead of physical reels that stop at a random moment, a video slot works with an algorithm that determines what outcomes are possible.
All video slots revolve around one basic principle: combining symbols on paylines. How exactly that works can vary enormously, but that principle remains the same. A classic slot consists of a fixed number of reels with a fixed number of symbols on each reel.
By playing, new symbols appear every spin (a game round you pay for), which can make a combination on the specified paylines. The more symbols in such a combination, the higher the win.