That's not particularly helpful or clear, so most players remember that rule as "take out dead cards, bring in answers." In many ways that is true, but it's not the actual point of sideboarding
List your cards on your grading company's submission center Via the submission center, you'll need to list the cards you'd like to have graded, following the instructions
Hexproof reads this card cant be the target of spells or abilities your opponents control. This means that most of your opponents cards that deal with your problematic cards are null and void
Many decks leverage this fact to sacrifice undying creatures for value since they return better off than they were before
Due to its limited availability and unique artwork, this card is highly sought after
Its a tool to get into position for a bigger play, but you wont kill fast enough to Time Walk someone out of the game with multiples