The Hitchhikers Guide to the Galaxy is very confusing

There is a spoiler about what happens in the beginning, if you haven't read it yet.

        I started to read the book The Hitchhikers Guide to the Galaxy by Douglas Adams.  So far I think it is about how the earth is going to be destroyed and what happens afterwards.  The main character is a man named Arthur Dent.  The book starts off with Arthur waj=king up to his house being destroyed so he lies down in front of it so they can't run it over.  Then his friend makes him get up and go to the bar where he tells Aurthur that the world will be destroyed in 12 minutes.  Then some alien things come or something.
        The first thing that I found confusing was that for a zillion pages all they talked about was Arthur's house getting torn down and him lying down in front of it.  I honestly do not see the point of that.  Yea it's sort of interesting, but it has nothing to do with the rest of the story, at least out of what I've read already.  I would have started the book more like this:
        It was a Thursday morning when Arthur Dent's friend Ford came and dragged him to the pub.  Now he was just sitting there waiting for the 6 pints of beer his friend had ordered.  Finally, they arrived.  "Now drink 3 pints of beer and I'll tell you why we came here," Ford had said.  Arthur drank his beers in question, thinking about how drunk he would be on the way home.  "The world is about to end."
        I would have started it more like that.  Not waiting a chapter or 2 for the stroy to really begin.  But I don't know, maybe that first chapter is important later on, so far I don't think so.
        Another thing that is confusing is when what ever it is appears.  The things in the ship.  That is what confuses me, i don't know what they are, I don't know who they are, where ther're from.  I don't know anything and it really confuses me.
        I just got into the book today so, sorry that it doesn't go into much detail.  I didn't know enough to write about much of anything.