The value of a z-score always tells us how many standard deviations we are away from the mean. For example, if the z-score is equal to 0, it is on the mean.
A positive z-score tells us that the raw score is higher than the mean average. For example, if the z-score is equal to +2, it is 2 standard deviations above the mean.
A negative z-score tells us that the score is below the mean average. For example, if a z-score is equal to -3, it is 3 standard deviations below the mean.