When you see the chords above the lyrics, as in a fake book, C, F, Bb without anything else means the major of those chords, i.e. C-E-G, F-A-C, and Bb-D-F (or any inversion of that major chord).

Although you are a beginner, if you are trying to actually play the chords by fingering them, DO NOT use Multifingered mode. Use FINGERED. In Fingered mode, you cannot get any chords with a single key, like you could in Multifingered. But by the same token, the chord accompaniment isn't bouncing all over the place just because you hit a single key. In Fingered mode, the chord is recognized ONLY when you hold three (or more) notes down. Thus, you can press the A, then add the C, then add the E and only when you add the E, all three notes down, will the accompaniment recognize the Am chord. I use this fingering mode all the time because not only can it detect the chord I want, but I can also play other notes in the accompaniment WITHOUT triggering a new chord. This can add a lot of variety to your arrangements.