Writing a book can be hard and there are many different answers to the question.
The most important thing to do at the start of any Story is to set the scene. Show the reader where the story is located, don't just tell them its in Upstate New York. Describe the location,use abstract words that the reader can interpret.
Using action to set the scene for a story is a great hook for the reader. Take a look at the snippet below and using what I've said in my answer see if you can improve it with some descriptive words.
'As the ESS Destiny pulled into orbit around the large earth like planet they were scheduled to survey, a dark ship appeared and started firing on them without warning.
’Red Alert! All command staff report to the Battle Command Centre‘ came the voice over the ship wide intercom. The Ship's command crew left their posts and headed for the Battle Command Centre.'