TrainingTraining is a triggered ability. “Training” means “Whenever this creature and at least one other creature with power greater than this creature’s power attack, put a +1/+1 counter on this creature.”
If a creature has multiple instances of training, each triggers separately.
Some creatures with training have abilities that trigger when they train. “When this creature trains” means “When a resolving training ability puts one or more +1/+1 counters on this creature.” (CR 702.149) (Whenever this creature attacks with another creature with greater power, put a +1/+1
counterTo counter a spell or ability is to cancel it: remove it from the stack without resolving it. A counter on an object or player is instead a marker that changes characteristics or interacts with rules or abilities; for example, a +1/+1 counter modifies a creature’s power and toughness. (CR 701.6; 122.1) on this creature.)
When this creature enters,
createTo create one or more tokens with certain characteristics, put the specified number of tokens with the specified characteristics onto the battlefield.
If a replacement effect applies to a token being created, that effect applies before considering any continuous effects that will modify the characteristics of that token. If a replacement effect applies to a token entering the battlefield, that effect applies after considering any continuous effects that will modify the characteristics of that token.
Previously, an effect that created tokens instructed a player to “put [those tokens] onto the battlefield.” Cards that were printed with that text have received errata in the Oracle card reference so they now “create” those tokens. (CR 701.7) a 3/1 green Boar creature token.