OMG I am a horrible person cause i saw this and said I would come back to answer it and never did. I am so sorry.
Ok you may have gotten your answer by now but to your second question you should never publish a picture/art/ or any work that does not belong to you especially if they say no. Most of the artist here are sharing their work with us willingly and have every right to take it down if people are taking work and using it without their permission. So please don't do that. Do not use someone's else picture/art/writing without their permission.
As for your first question. That kind be tricky. Even if you don't know much English you can write it in your native language. You should be able to find groups here that have folders for those situation or even groups dedicated for that so don't let that stop you if you want to write.
A story is a bit more difficult question. For any story you need a plot, characters, a setting, conflict and solution- this is as basic as it gets. Fan Fiction is always a slightly easier way to work on your writing skills since you already have characters to work with and plot lines for them. The fun thing about writing then is creating situations that you may have liked to see on a show while trying to keep the characters as close to their original personalities which can be tricky.
So I think the best way to explain it to you is to use an eg.
So first think about what you want your story to be about. Mine will be about two people in love.
Now think about the characters. How old are they? Genders? How are the different from each other? For example let's say the couple will be a tall girl and a short boy. They are in their late teens.
What's their history and relationship? Example lets say that these two are rivals at school. They known each other for a long time.
How are they going to fall in love? In other words how are you going to write out your plot line for your story. Example let's say its a rare day that our rivals are very civilised with each other. They decided to keep things just to friendly competitions like seeing who is the better cook and who can eat their food faster. They laugh, joke and suddenly feel very relax around each other.
Is there a conflict? Most storied tend to have a conflict in them but sometimes you may not have one because of the style of story you are writing. If you do have a conflict remember to think about the type of conflict. Is it internal or external? Internal would mean for examples let's say the girl is aware of her feeling for the boy but is uncertain whether she should tell him because she does not want to be rejected. An external conflict could be that both are actually in a relationship but with someone else.
Then a resolution. Will you solve the problem or will you choose to leave it as is. How will your story end.
And now lets put it together
They won't arguing for once. Usually they would be at each other's throats, clawing and screaming. Their fights really did get too physical sometimes. It was starting to leave both of them black and blue and sore. They knew they should stop. They both knew they should move on. But it's been going on for years, this stupid rivalry. Her boyfriend hated it, his girlfriend hated her. But what could they do, old habits died hard. They have been bumping heads since the day they realized she was going to always be the taller one and he was stuck being permanently short. They both started fighting when they realized they were drifting and were both too scared to say something to put them on the same boat. She regretted it, not saying anything. She always felt like she should have said something because she knew he was bad at saying the right thing. He was always too scared and now she was to. They both knew they were in love with each other but neither chose to tell the other. This was their abusive relationship, loving each other while loving someone else who they knew deserve better.
"Come one admit it, I am the better cook and I ate faster than you"
"Continue dreaming you little dork. I won, both of them."
They laughed. They cried and they ignored the sounds of their breaking hearts.
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It's a bit rough but I hope you can see how I blended in all the points I made above. The most important thing when writing is to plan. Once you know where you want start, just write and don't worry about anyone else.