cord and lightning symbol and red flashing battery on screen

that is a recharge screen. the phone is recharging but not ready to be powered up for use at that state even plugged in. Give it a few minutes and it should be in a usable state.

if the device fails to get to the point where it's charging see this link:

https://support.apple.com/en-us/HT201569

If nothing happens then it’s likely the battery is completely gone.