Here's what happened in the first chapter: the mc is a girl and is in a library with 2 friends (girls) that are studying while she's looking at an rpg-like book that tells her that she's a strategist. All of a sudden she is then brought in another dimension/back in time and there she encounters the king of a country and is regarded as a disceple of the best strategist of that world. As they asked her help the country gets attacked. She makes a strategy after having seen the future with the book that took her in this world, but the events don't go as planned and she's in trouble.
Thank you for taking your time to read ^^