"Choose a <something>" is just a choice you make as the spell or ability resolves. In the case of a land, since it is not a spell or ability, you just choose a value when you play the land for turn or when it enters the battlefield for some other reason. So, you play the land for turn and choose "Vampire" as your creature type. The game (and each player) now just "knows" that the creature type chosen is Vampire.
The second ability works like the mana ability of every other land or permanent. You tap it to get 1 mana. In this case, you get to choose the color of mana you add to your mana pool and you can only use that mana to cast a Vampire creature spells. Is there something specific that is throwing you off? I know many new players conflate "land" and "mana" and think that by tapping a Llanowar Elves for green mana, that they can get a land from their library. That is not the case.
Mana is a concept in the game of Magic (there might be a better way to describe it). Essentially, you use lands or permanents (like the Elves above) to generate mana. This mana then sits in your mana pool until it is used or until the game moves to a different phase or step.
There are two different "taps" on the card. The top one lets you just tap for generic colorless mana while the bottom one taps for any color mana but can only be used to pay for the creature type you declared when playing the card. The top one just lets you tap Unclaimed Territory for colorless mana in case you play anything else other than the creature type.
Just remember you only get to tap for one or the other, not both at the same time.
The common analogy is a vending machine (although it's usually used to explain paying the cost of one ability on each of two different cards, it works just as well for two abilities on one card). Unclaimed Territory is a vending machine with two items in it: a colorless mana, or a mana of any color with a restriction on what you can spend it on. Each has the same price: tap Unclaimed Territory. You pick the item you want, pay the price, and get that item.
How does Unclaimed Territory work? I'm new to this game and do not understand the first two actions of this card.
How does "choose a creature type" work? How would I play that?
Also, the second ability, what am I adding to my mana pool when tapping?
The second ability works like the mana ability of every other land or permanent. You tap it to get 1 mana. In this case, you get to choose the color of mana you add to your mana pool and you can only use that mana to cast a Vampire creature spells. Is there something specific that is throwing you off? I know many new players conflate "land" and "mana" and think that by tapping a Llanowar Elves for green mana, that they can get a land from their library. That is not the case.
Mana is a concept in the game of Magic (there might be a better way to describe it). Essentially, you use lands or permanents (like the Elves above) to generate mana. This mana then sits in your mana pool until it is used or until the game moves to a different phase or step.
Just remember you only get to tap for one or the other, not both at the same time.
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