look because you have just started out don't worry too much about being able to name the all the notes, just try to have fun and gather as much information as possibile, as for what 'Sivert Skaaren' said, the key notes of a scale are the thirds and sevenths, these will determine what "sound" the chord has (with the exception of dim and aug chords.) It is important to know all the chordal tone though (1,3,5,7) the fastest way to learn this is arppegiate ever chord you can.

As for the cycle of fifth's, this relates to the order that the keys go in. You start with C (no sharps or flats)then go up a fifth you land on G (F#) and so on. The cycle of fourths goes in the other direction C then F(Bb) etc.

Hope i helped:)