How to insert divs in a page in order to organize content

I am creating a website using wordpress as CMS site and the loop as blog.

Meanwhile, when I am doing all the preparations regarding info of the products. I want to split every page of products in two: in one side picture of products and technical features; and in the other one description and other issues.

I made a div container, and two divs. On a page I took de Html tab and I inserted:

<div id=”contenedor”>
<div id=”izq”>hola</div>
<div id=”der”>chau</div>
</div>

and the css code for these divs are:

#contenedor {
clear: both;
float: none;
height: auto;
width: 100%;
}
#izq {
float: left;
height: auto;
width: 40%;
background-color: #399;
}
#der {
background-color: #900;
float: left;
height: auto;
width: 60%;
}

But the divs are not display in the preview image.

How could I insert divs?

Thanks in advance