You're not alone, this is actually a common problem, people expect artists to be able to write comics too but in the west there are no resources aimed at teaching artists to write or even just telling them that no, being able to draw doesn't automatically teach you this learnable skill. So there are all these artists berating themselves for not being great plotters as if it's just some magical ability a person might pick up through osmosis and not a learnable skill.
I wrote in detail on the basics of story in a guide I wrote the other week that goes over a lot of basic comics stuff. A basic summary is:
A story should document HOW a protagonist came to be significantly different in circumstances than they were at the start of the story, either through a change to themselves or a change to the world. So the first thing you need to think of is "what is the central change or journey my story is about?" ie. "How an orphan boy with a horrible foster family came to become a powerful wizard, defeat the evil dark lord and build a family." or "How one guy learned the truth of the oppressive regime he lived under and made the public aware, sparking a rebellion that lead to his eventual death" or "How one girl who wished to escape her mundane life went on a magical adventure that made her realise the value of what she had."
A lot of the time, people make the mistake of coming up with a really cool concept like "It's about a team of sentai... but they're all demotivated college stoners!" or "It's about a space pirate, and he has this really cool ship and a robot friend and there are aliens and..." or "An ordinary office lady gains the powers of a god!" but it's always just going to meander without direction if you never thought out what the actual story is. Even if it's really well-drawn and the dialogue is great, it still has no story.
So my advice is to ask yourself: What journey or change do you want to tell a story about?
Common setups are things like:
"I was an ordinary person with a boring life until this strange magical person showed up and asked me to go on a quest to get this macguffin! By going on the quest I discovered that the biggest problem with my life was ME and after the exhilarating climax of the quest, I returned to my old home way cooler."
"I was lonely and struggling to find love until this absolute weirdo showed up and we had to interact regularly due to work/life circumstances, but eventually I came to love them and struggled through every problem in my path to be together and then we got married!"
"I was a cog in the machine of a dystopian society until a chance encounter gave me a glimpse of what was underneath and I couldn't be ignorant any longer. I went on a quest to destroy it that lead to my death... maybe though... I planted some sparks of rebellion and hope?"
"I was an ordinary person having an ordinary day when I got trapped in a place with a killer/monster picking off everyone around me one by one. Through a brutal struggle, I was able to survive and outsmart the killer/monster, destroying it and becoming a hardened badass in the process."
So instead of just the cool stuff in your story, think about the arc of the story, the message and where you want the end point or conclusion to be. See what genre it might fit to, and what the conventions are of that genre to follow or subvert. I find it really helps to shape the story.