Q: I download the 10.0 and my facebook want work

You will need to restore the device as New via iTunes:

Place your Device into DFU Mode

 

Follow these steps to place your iOS device into recovery mode. If your iOS device is already in recovery mode, you can proceed immediately to step 6.    1. Disconnect the USB cable from the iPhone, iPad, or iPod touch, but leave the        other end of the cable connected to your computer's USB port.    2. Turn off the device: Press and hold the Sleep/Wake button for a few seconds        until the red slider appears, then slide the slider. Wait for the device to turn off.                 * If you cannot turn off the device using the slider, press and hold the                 Sleep/Wake and Home buttons at the same time. When the device turns off,                 release the Sleep/Wake and Home buttons.     3. While pressing and holding the Home button, reconnect the USB cable to the        device. The device should turn on. Note: If you see the battery charge warning,        let the device charge for at least ten minutes to ensure that the battery has some        charge, and then start with step 2 again.   4. Continue holding the Home button until you see the "Connect to iTunes" screen.        When this screen appears you can release the Home button:   5. If necessary, open iTunes. You should see the following "recovery mode" alert:   6. Use iTunes to restore the device.

 

If you don't see the "Connect to iTunes" screen, try these steps again. If you see the "Connect to iTunes" screen but the device does not appear in iTunes, see this article and its related links.

 

Note: When using recovery mode, you can only restore the device. All user content on the device will be erased, but if you had previously synced with iTunes on this computer, you can restore from a previous backup. See this article for more information.

 

[Permission to use part or all of the above has been granted by Kappy, exclusively, to theratter.]

FWIW, I for one don't understand what you downloaded and for what. theratter seems to think you downloaded iOS 10 which unless you and "everybody on facebook" has a developer account, isn't possible. Could you give more detail as to what it was you downloaded and from where?