Below are some of the Help Topics that would most likely answer your questions on how to play Endless Chaos and some other features found in the game.
From official site
How to Equip Weapons and Armor
Once you have purchased equipment such as weapons and armor, head over to the Inventory section by clicking the link at your information bar.

Once on the page, just click on either [Weapon] or [Armor] tabs. Once there, just click on the desired armor/item to equip. There will be a confirmation message that the item has been equipped.

How to Battle Players (PvP)
Go to any Wilderness map, then select the Player VS Player tab; after which select your opponent by clicking the [Fight] button beside the player's info.

After which you will be taken to the PvP battle screen.
PvP Battle Basics
Once the PvP battle has started, you'll be able to see the battle screen:

The battle is played out in turns. For each turn you can select from the command bar the actions that you can take.

Each action consumes 1 turn. The battle ends under one of these conditions:
REWARDS
Depending on the outcome of the battle, you will gain rewards form the battle.
BATTLE TIPS
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