Edit in JSFiddle

<header>Header Alanı</header>
<nav>Navigasyon Menü Alanı</nav>
<article>
    <aside>Sidebar Alanı</aside>
    <div id="icerik">İçerik Alanı
        <section id="ust">1. İçerik Alanı</section>
        <section id="alt">2. İçerik Alanı</section>
    </div>
</article>
<footer>Footer Alanı</footer>

header{
    background:#ccc;
    height:35px;
    border:2px solid #000;
    border-radius:5px;
    text-align:center;
}
nav{
    background:#ccc;
    height:20px;
    border:2px solid #000;
    margin-top:2px;
    text-align:center;
    border-radius:5px;
}
article{
    height:200px;
    border:2px solid #000;
    border-radius:5px;
    margin-top:2px;
}
aside{
    background:#ccc;
    width:20%;
    height:95%;
    float:right;
    border:2px solid #000;
    margin-top:2px;
    margin-right:2px;
    text-align:center;
}
footer{
    background:#ccc;
    height:20px;
    border:2px solid #000;
    border-radius:5px;
    text-align:center;
    margin-top:2px;
}
#icerik{
    width:75%;
    height:95%;
    border:2px solid #000;
    margin-top:2px;
    margin-left:2px;
    text-align:center;
}
section#ust{
    background:#ccc;
    height:75px;
    border:2px solid #000;
    margin-top:2px;
    margin-left:2px;
    margin-right:2px;
}
section#alt{
    background:#ccc;
    height:75px;
    border:2px solid #000;
    margin-top:2px;
    margin-left:2px;
    margin-right:2px;