Support occurs all over the rink at all times by all players on the ice. 

Every moment a player is on the ice he should be continually supporting his teammates.

On the offensive - when one forward has the puck, the other forwards should be finding clear ice and then have the stick blade on the ice where the puck carrier can see it. This is referred to as the target. The puck carrier needs a good target to get the pass there.

On the defensive - when one forward is checking the other team’s puck carrier, the other forwards should be supporting him. The forward furthest from the play should pick up his check (one foot from his check and between our net and his check). That is what is meant by covering your man. Meanwhile, this checking forward should keep an eye on the play and be ready to react quickly.

Note: the better players in pro hockey always know where the puck is, where their teammates are and where the oppositions’ players are. They know what direction all are going in and how fast all are going. They are able to anticipate where the play and where the puck will be. Simply put, that is why you see better players arriving at the same spot at the same time as the puck. Often to change the flow of the play or to better an offensive play.