Multiple instances of lifelink are redundant.

is the energy symbol. It represents one energy counter.

Energy counters are a kind of counter that a player may have. They're not associated with specific permanents. (Other kinds of counters that players may have include poison and experience.)

Keep careful track of how many energy counters each player has. You may do so by keeping a running count on paper, by using a die, or by any other clear and mutually agreeable method.

If an effect says you get one or more , you get that many energy counters. To pay one or more , you lose that many energy counters. Any effects that interact with counters a player gets, has, or loses can interact with energy counters.

Energy counters aren't mana. They don't go away as steps, phases, and turns end, and effects that add mana "of any type" to your mana pool can't give you energy counters.

You can't pay more energy counters than you have.

Each Vehicle is printed with a power and toughness, but it's not a creature. If it becomes a creature (most likely through its crew ability, but the Kaladesh set includes other such effects), it will have that power and toughness.

If an effect causes a Vehicle to become an artifact creature with a specified power and toughness, that effect overwrites the Vehicle's printed power and toughness.

Vehicle is an artifact type, not a creature type. A Vehicle that's crewed won't have any creature type.

Once a player announces that he or she is activating a crew ability, no player may take other actions until the ability's been paid for. Notably, players can't try to stop the ability by changing a creature's power or by removing or tapping a creature.

Any untapped creature you control can be tapped to pay a crew cost, even one that just came under your control.

You may tap more creatures than necessary to activate a crew ability.

Creatures that crew a Vehicle aren't attached to it or related in any other way. Effects that affect the Vehicle, such as by destroying it or giving it a +1/+1 counter, don't affect the creatures that crewed it and vice versa.

Once a Vehicle becomes a creature, it behaves exactly like any other artifact creature. It can't attack unless you've controlled it continuously since your turn began, it can block if it's untapped, it can be tapped to pay a Vehicle's crew cost, and so on.

You may activate a crew ability of a Vehicle even if it's already an artifact creature. Doing so has no effect on the Vehicle. It doesn't change its power and toughness.

To attack with a Vehicle, it must be a creature by the time the declare attackers step begins, so the latest you can activate its crew ability to do so is during the beginning of combat step. To block with a Vehicle, it must be a creature by the time the declare blockers step begins, so the latest you can activate its crew ability to do so is during the declare attackers step. In both cases, players may take actions after the crew ability resolves but before that Vehicle has been declared an attacking or blocking creature.

When a Vehicle becomes a creature, that doesn't count as having a creature enter the battlefield. The permanent was already on the battlefield; it only changed its types. Abilities that trigger whenever a creature enters the battlefield won't trigger.

If a permanent becomes a copy of a Vehicle, the copy won't be a creature, even if the Vehicle it's copying has become an artifact creature.