Andrew,
Great question.

I think that there's no single answer, but please read on.

Many (most?) times, the write / composer starts with lyrics and adds a melody that suits.
Think: Hal David and Burt Bacharach, or Bernie Taupin and Elton John.

On the other hand, think The Bee Gees, where they would compose a melody and then write lyrics to suit. Quote:
“The style of writing songs doesn't change at all, really. Melody first, lyrics second." - Robin Gibb"
and quote:
"They always wrote the music first, then when they'd get together in the studio, they'd play the music and come up with the lyrics on the spot. They never wrote lyrics ahead of time."

So if you've got a melody, think hard about what concepts you may have had in mind when you wrote the melody. Use that as an inspiration.

Case in point: I wrote the melody to this song before I had any lyrics. I wrote the lyrics to match the melody.

If I can do it, you can too smile Be positive.

Good luck!

BIAB & RB2026 Win.(Audiophile), Windows 10 Pro & Windows 11, Cakewalk Bandlab, Izotope Prod.Bundle, Roland RD-1000, Synthogy Ivory, Session Keys Grand S & Electric R, Kontakt, Focusrite 18i20, KetronSD2, NS40M, Pioneer Active Monitors.