-----As you already have the lyrics
, and are already singing a tune
- old rule of thumb is one melody note for each lyric word. Ma-ry takes two, bea-ti-ful takes three. Sing the tune one word at a time and the notes you need for each word will be up scale or down scale - duhh - that goes with out saying - just write down which and by how much. After the notes get written (in standard notation) you should be able to see a little wave action in the melody line - no wave action will be boring, 20 foot breakers may be too much.
One to two chords per measure - the melody notes being used dictate how many, i.e. the melody notes and the chord under it should contain some of the same notes - when the melody moves on to a new set of notes not found in the old chord you need a new chord. As long as the melody is staying with notes within the old chord there is no need to find a new chord - sus chords, extensions or inversions of that old chord
keep the progression moving. Shoot for at least one chord per measure.
I think your song will fit into the classic four line verse. First two lines contain a full chord progression - I IV V I or which ever one you have picked. Then the next two lines repeat that same progression. Chorus can be the same, or you can change it - up to you. But, I'd suggest the verses stay with the same progression.
The hook -- your chorus is probably the best hook. Beyond the chorus the hook can be a riff that is repeated. Between your chorus and the melody you come up with the hook may just fall in place.
It's your song have fun with it.