To move with the ball in Gaelic Football it sounds complicated but is in fact quite straightforward.
The player with the ball can move 4 steps before they must either bounce the ball (like basketball) or bounce (hop) the ball off the foot and back into the hands, called a Solo.
The player cannot however, hop the ball in series. In other words, after a bounce is performed, then the next action MUST be a solo. If you perform a solo though, then another solo is permitted, indeed you can do solos in series with no issue.
Steps (or travelling) is called when the player moves more than 4 steps without performing either a bounce or solo and is a foul.