Ah, I'm experiencing that right now.
But, I think I may be able to help you.
You have a plot, others like it, but you don't know how to continue it.
First of all, I'll ask you this: do you like your idea? Do you like the way your story is going? You need to et that part cleared up before you continue, because if you aren't really into it, not enjoying it, you don't like it, you may not get very far writing it. It just won't work out.
So answer that to start off.
If you do like where it's going, and are excited to continue, let's talk about the next part: you don't know how to continue your plot. Don't worry. This happens. People post stories all the time without knowing what they're aiming for (me included).
Plan it out. Think of different scenarios and directions you can bring your story. When you have this done, pick the ones you like best. Then, depending on how many you choose, do any of the following:
1.) Pick from them.
2.) Ask for another's opinion.
Or, 3.) Write a chapter for each of your ideas. Yes, this may take a while, but it could help. If you do this, then choose the chapter you like best. After you do that, do what you want with it, then maybe, again, ask someone to read it to see what they say. Then post it. Also, some people like to give you ideas of what you should do next. Just ask! Ask your readers if there's anything they want to happen, because you never know - it may spark an idea or give you inspiration. The worst thing you could do is not try anything.
I hope this helps somewhat. If it does not, just tell me, and I'll think of something else.
Thanks for the question, and I hope this helps you! Good luck, and have a great day/night!