Do you want to make your own song? Maybe just want to "trying out to do-it-yourself"? If its possible...

We now assume, that you have your "music editor software" installed and ready.
Where to start?

Basically there are to ways to start:
1) Start with music. Or
2) Start with a story.

For me it's easier to start with the text.
Think about a little story you want to tell. Try to say it as straightforward and simply as possible. Focus on the chorus-text. That's the story of your song about. The more people can relate the better. Give them something to think about. To smile or agree about.

It doesn't matter if you start with the music or the story, in both cases you have to be aware of the structure of a song.

The sections of a song:

-Intro
-Verse
-Bridge
-Chorus / Hook
-Outro

Songs are put together with some or all of these parts.

Intro

It mainly contains instrumental music before a verse starts. But not all songs use an intro. If you don't want to start with a "big bang" use an intro.

Verse

The verse is the story, the details of the song. The writing is typically arranged in a rhyme.
When you write down your story for the song, watch out for the length of the sentence. Because you'll repeat the verse a few times, the sentence length must fit into the same verse several times.
If you have a melody, try to sing the sentence. Rewrite it if it doesn't fit.

Bridge:

For me the bridge is the glue between the verse and the chorus. If they don't fit together (if there is no "nice wave" flowing) it needs the right glue. If you listen to your music after a few days and you can't hear the glue anymore (if it's a importand part of the song) you used the right formula for the glue. Of course you know where YOUR OWN glue is. It's your song that you are listen to. You know what i mean...

Chorus

When a song comes to the "chorus", you may recognize it immediately. Normally it sounds a bit fuller, mostly louder, maybe the melody is also slightly higher. It is usually very short. It may be the highlight of the song which has built up for long and now finally reaches.
Anyway, it's the part of the song, in which the same old phrases are repeated. It is the part that gets you hooked up, it will not let you go. This short piece melody will haunt you day and night. It will float around in your head and you will whistling it on the street.
Anyway, that's definitely the goal of the "chorus" when you compose the song. "Show no mercy" to the listener. They mustn't  escape the hook.