Thank you so much for your reply. You are right I should have started earlier and added the story in the game, not on the page.
Story:
You are leading a tribe after robots from the future attacking to extinct humanity. These robots are full of rage because humans destroyed many of them and they lived under the shadow of humanity for a long time as servants. Now they want to rule the world. Create your tribe, upgrade your village, and army, and get resources to fight against robots.