cant understand steins gate....?

You dont understand anything on third episode ,you start understanding after the 5th episode but if you still want to understand keep reading ,i will explain quickly: the microwave is a time machine ,it can only send very small amount of data and thats why the bananas become green jelly , the messages use small amount of data and thats why they can send messages ,so after Okabe saw Christina dead he panicked and when he left the place he sent a message to his friend saying that she died ,his super hacker friend was performing an experiment and his cellphone was connected to the microwave and since the microwave is a time machine the super hacker's cell phone recieved the message but not in the present but in the past ,this message caused events to change so Christina didnt die and they transfered from world A to world B (you will understand these 2 later) ,Okabe is the only person who noticed because he has a special ability (i forgot its name)makes him realise the changes in timelines

I don't remember what happens at specific episodes but basically, Okabe and his crew developed a device that can send text messages to the past, relaying information from the future that their past self would have not known, that could potentially alter the future if they take the advice to heart. Everyone is getting introduced first so that you get to know their problems and stuff.

Once all that happens, Okabe makes a tragic discovery that he meddled in the past too much, and caused an organization called SERN to take interest in their machine (because they were trying to achieve time travel as well) and cost Mayumi her life. By that time, Kurisu has made a functioning time leap machine where Okabe can send the information of his mind back into the past and have his past self try to alter the future with the gained knowledge. He basically has to undo everything he changed to save Mayumi and everyone else.

Running out of characters (word limit) so I'll leave it at that. It's good.

At first, me neither, I didn't understand at all. But thanks to my brother (who proposed me to watch Steins;gate), I finally understood and I was able to continue the series...Now I will explain to you the best I can...

Okabe and his group built a microwave which is in fact a time machine. They made a lot of tests of sending bananas to the past, but it always turn them in jelly because the bananas are too big : it's like trying to fit a sponge in a hole too small. That's why they turn into jelly...One day, SERN, an organization who is interested in time travel too, made a conference about time machines and Okabe decided to come, just to see what it was about. After that, he saw Kurisu dead. Outside, he sent a message to Daru his friend, telling that Kurisu was stabbed. As soon he sent it, all the people outside suddenly vanished. Because of that, Okabe started to panic. On top of that, later, he saw Kurisu alive and well. But earlier, did he saw her dead ? Okabe doesn't understand what it's happened.

I'll say this : If you received a message telling you that you'll die, you will certainly do all you can to avoid it, right ?

That's what my brother told me to make me understand a little bit more. That's why Kurisu is alive. Back at the lab, Okabe and his friends try to find an other way to do time travel and they realized that sending text messages work. One day, SERN concluded that Okabe has gone too far, so they broke in the lab to seize Okabe and his friends. Since the childhood friend of Okabe, Mayuri was not needed, SERN killed her...Since that day, Okabe will do all he can to save Mayuri.

I did my best to explain the story to you. I hope that was ok...