Can you train at poker by yourself with a deck of cards?

Do you know all the rules for the different variations of Poker? Do you know how to properly shuffle a deck of cards? Do you know how the blinds and raises work in Texas Hold'em? Do you know what to do when a player is away from the table when it is their turn to post a blind? Do you know how to set up a split pot or multiple pots? Do you know how to call the hands? Do you know what to do with an exposed card?

If you answered yes to all these questions then you can probably train yourself.

If you want to train yourself for friendly home games, then go for it. If you want to train yourself in order to become a poker dealer in a casino, be aware of the fact that poker dealers have to know how to deal more than one version of the game, accurately, and that casinos are very conscious of following the rules of poker and prefer dealers that are trained by a dealer school.