After finishing the tutorial, tap the "Event" button at the top to display a list of categories. Check any that have a notification number next to it. This indicates that there are rewards in that category that can be collected.
Gear
Equip the best gear equipped in all of your slots. Then, fortify your gear as much as possible. To do this, tap a piece of gear, then tap "Fortify". You can spend gold to improve the stats of that item. Your over "Might" represents how strong your team is.
Ranks
Each level has three stars that can be earned. Complete optional objectives, such as completing the level under a specific time limit, killing a certain number of enemies, etc. Try to get all three stars in each level as they are required to open the warlord chest. It contains rare rewards.
Skills
Use your skills often. The first two skills usually have quick cooldowns. Use them repeatedly to quickly take down enemies. Your SP ( blue bar) will recharge slightly each time you land a normal attack. Use a mix of normal combos and skills to take down your opponents.
Treasure
The "Treasure" icon next to the event icon gives you a chance to win hero shards, equipment, and other items. The blue shrine on the left allows you to draw for equipment and hero shards. The orange shrine to the right allows you to draw for rare gear. You can draw from the orange shrine for free every other day. You can draw from the blue shrine for free every few minutes.