Hi!!!
There is a fairly simple way. If you only want to remove Author, Date and Category from the posts that are displayed on the home page, then you will have to make some changes into the index.php in your theme folder.
1) Open your theme folder (located in wp-content\themes\your theme name)
2) Locate the index.php file. Create a backup and then edit the original file. In case something goes wrong, you can always restore the original file.
3) Open the original index.php and locate the following functions
get_the_author()
the_time()
the_category
4) Comment out the function lines and the markup from where it is getting generated.
E.G
If it is something like this
<h2><?php printf( esc_attr__( 'About %s', 'twentyten' ), get_the_author() ); ?></h2>
then turn it into this
<!--<h2><?php //printf( esc_attr__( 'About %s', 'twentyten' ), get_the_author() ); ?></h2>-->
If you are not getting the idea, then please go through this
http://codex.wordpress.org/The_Loop