EagleCad Warning errors
From what I can tell, it appears that a pin on many of your parts is designated to be a POWER connection. This means that Eagle expects that pin to be connected to a Vcc from the supply1 or supply2 library.

If you are connecting power manually using a net not connected to Vcc, then Eagle will give you these errors as the expected POWER connection is not present.

It's just a safety check. In industry you would probably want to designate things properly and connect things according to specifications. In my board I sometimes have nets named 5V, 12V, etc.. and sometimes get these errors as the ICs are not connected to a Vcc (strictly speaking).