Leveling up your hero is one of the best ways to get ahead in Operation: New Earth! As your hero grows, they gain Skill Points which can be used to unlock hero-specific abilities.
Hero XP can be acquired in several ways. You can get it as a reward from certain Daily and Alliance Missions, as a prize in the Gambling Den, as part of a cache, and even by shooting down flying saucers over your base! Hero XP can also be purchased in both the Item Store and the Alliance Store using Shards and Alliance Credits respectively.
Once you've leveled up a few times and have some Skill Points to spend, visit the Hero Skills section.
Here you'll have a ton of different skills to choose from and level up! You can use these skills to add passive bonuses to most everything! This includes increasing the speed of troop production or research to increasing the attack and defense statistics of all your troops and many more.