What do I need to do?

I need to reset my iPhone, i have everything backed up to iCloud so do I just need to sign out if my ICloud then reset it

No need to sign out, just go to settings > General > Reset and select "Erase all content and Settings"

This only resets your device, it doesn't touch your iCloud.

You use the Erase all content & settings option on the phone or Restore using iTunes.