Your game code can make decisions while the game is running by use of if. if works just like it does in the English language.
*English* If the character name is Bob then give him 100 hit points. *Code* If charName = "Bob" then hitPoints = 100
*English* If the player has no lives then the game is over. *Code* If playerLives = 0 then gameOver = true
if playerLives = 0 is a comparison. You can also make other comparisons.
<> means does not equal.
*English* If it isn't Bob then he gets 50 hit points. *Code* If cName <> "Bob" then hitpoints = 50
> means greater than.
*English* If the player has more than 0 lives the game isn't over. *Code* if playerLives > 0 then gameOver = false
< means less than.
*English* If Bob has less than 1 hit points then he is dead. *Code* If hitPoints < 1 then BobAlive = false
<= means less than or equal to.
*English* If the enemy building has less then 50 hitpoints bob can take control of it. *Code* If buildingHp <= 50 then buildingOwner = "bob"
>= means greater than or equal to.
*English* Bob needs at least 50 mana points to cast fireball. *Code* if manaPoints >= 50 then CastFireBall()