HTML5 CSS3 LAYOUT

I am beginner in web design and i have a problem with fixing the layout of my webpage. I want to make a two column content area with aside element but i can not find the right way. I have tried to reduce the width of section but it did not work. Can someone tell me a good option about my css code? Thanks!enter code here

article, aside, footer, header, main, nav, section{
    display: block;

}
#wrapper {
         margin:0 auto;

         width: 96%; /* Holding outermost DIV */
    }
#header {
    margin-left:auto;
    margin-right:auto;
    background-color: #165E00;
    width:1000px;
    color:white;

    padding:10px;


}
strong text
#section {
    margin-left:156px;

    font-family: Sans-Serif;
    background-color:#FFDD00;
    height:1900px;
    width:1000px;
    padding:10px;   
    text-align: justify;    
}