I began trying to write a book yesterday and saw that what I wanted to write in 10-15 pages I wrote in two. How do I lengthen the book so it won't be this short?
This is going to come across as simplistic, but it seems to me that you have to have something to say and a reason to say it. Thus, you have to go back and ask the question, what are you trying to say. This is not easy and may take multiple revisions before you figure it out. But if you do not do it, your readers, equally confused, may decide to spend their precious attention somewhere else.
There are a thousand ways to write a novel and depending upon the skill of the writer, most of them will, eventually, produce something worthy of reading. The internet is a great resource to educate and confuse the (beginning) writer. Books, articles, and podcasts abound. Sample repeatedly until you find something that works for you. And by "works for you", I mean that after consuming the advice, you sit down and produce something worthy of having someone else read. Nodding your head and saying, Ah Ha, are not enough.
I will offer two aspects that I personally think are key: context and emotional destination. Short paragraphs about each to follow. First a short bit of plot and characterization: Mary goes to the store, sees an injustice, speaks out, gets some blowback form some and praise from others, and learns something about herself.
This needs context to "thicken the soup." What was Mary's upbringing? Is this the first time or the tenth time that she has spoken up in this fashion? Is she financially and socially secure or just hanging on? Does she live in a community that values social justice or does the community think that social Darwinism is just great? What time of year was it? Was the weather good or miserable? Did the store have what she wanted? How old is she? And so on and so on. Everyone of the answers to these questions exerts a pressure on Mary and enriches the story. How much context do you add? Damned if I or most writers know how to answer that question. The best answer that I have is to write more than you need and edit out the excess during revision.
Characterization is my way of saying, where does Mary start and where does she end up? How does she change during the course of the story? How does that affect (or not affect) the other people in the story? How do you want the story to end? What has to happen in the story to bring that about? Are there interesting side trips to divert (and possibly confuse) the reader? What do you want the readers to learn from having read your story?
There is a whole lot more to writing but taking small steps with interlaced contemplation of pluses and minuses can take you father than you might initially imagine.
It depends. Did you say what you wanted that chapter to have in two pages effectively? If so, that’s great. It is really about how you feel with respect to what you’ve written with respect to length, in other words, do you feel that you could lengthen what you’ve written in two pages to fifteen? Or are you happy with what you could have said in fifteen but said in two? If you want fifteen pages, the try to make it fifteen pages; thereafter compare, which of the two is more effective for yourself subjectively? Then, the real question is, which would you rather read, the two pages in a book as a result of the effect or the fifteen as a result of the effect? Be honest with yourself when answering these questions.