Free the clasps along the battery slot. And the push the front assembly out from middle housing with effort.
We can see the USB board but we can't tear it down directly. Because 1. The USB board flex connector is connecting on the back of the motherboard. 2. If want to remove motherboard, the LCD screen need to be removed at first. 3. The USB board assembly comes with two touch keys together but they are placed under the touch panel.
So we have to remove the motherboard and LCD screen at first next.