On my first
diagram I managed to eliminate several errors but there are
still 2
What is the
solution ?
You have to connect a component called PWR_FLAG to your VCC and GND to let Kicad know that this is a power input (which it then can use to verifiy that such nets are connected to pins that are configured to be a power input). As a quick hack you can just add it to the leads of the chip in this case (attached your modified schematic)
But typically you do that at where you input the power, like a connector of sorts: there where your power is coming in, you connect that to VCC and GND and also add the power flags (and it is also a good reminder for you, that you don't have a way to connect power to your circuit in its current state :) ).
(there are probably some tutorials on the 'net to explain in more detail the PWR_FLAG)