Hi, thank you for reaching out. As for my advice, by revising your story means that you're correcting it. What I do is I copy/paste my chapters to Microsoft Word and see if there are any typos or grammar errors. If much possible, I also add or remove certain contents that I find off-putting. Since I started writing my fanfiction when I was still in junior high school (completed the story on my university), I had to change most of the parts.
I've read a partial of your story and yes there seems to be several typos and grammatical errors. If you're planning to add more dialogues and chapters, feel free to do so. It is your story, so it's up to you on how should it look like after being revised. But, just don't change the plot. It would be weird if you happened to do so.
Though I say all this, I haven't even finished revising my fanfiction (rip me T_T) Am kinda pretty busy with my online classes and assignments, and most of the time, I just play video games.
But welp, I guess that's all for my advice. Thanks for giving my story a credit. Knowing someone getting some inspiration from my work is an appreciation.
Have a good day!