Video Poker is Poker but on a computer / machine. It is the same game, but you are not playing with physical cards and with a live dealer, all that is the job of the machine especially if you play the game in casino online.
So how to play:
Firstly you insert your money. In some places you will in fact insert a barcoded paper ticket, which has credit on it. This is just to eliminate the use of physical money.
Once your 'money' has been received you must place a bet on one or more credits, then you press the 'deal' button. At this point you are given cards. As in a normal game of Poker you can discard some for another, which are all drawn from the same virtual deck.
At the end of the round the machine will pay out if your combination of cards matches that of a winning combination, specified on the pay table.
The pay table tends to follow the same combinations of a normal poker game. It can vary from machine to machine, depending on popular hands and the decision of the game operator. But in general a normal pay table will start with the lowest hand for payout as a pair of Jacks, the rest of the combinations then follow that of traditional Poker.
So you will receive money or credit for, two pair, three of a kind, a straight (5 cards in sequence but different suits), a Flush (5 cards from the same suit), the full house (one pair and three of the same), Four of a kind, a straight flush (5 sequenced cards of the same suit) and finally the Royal Flush (10, Jack, Queen, King, Ace of the same suit) this being the combination with the largest pay out.
So video poker is as simple as that. Place your bet, test your luck and see what happens.