Since you are a beginner. I will make it straight forward. Below is extraction of your code. I used internal style sheet. Your example you are using external style sheet.
        Using float attribute you can set it to left and right. Here is used float:left to alight one div to left and float:right to alight other one to the right.
        Each opened  tag has to be closed  tag.
    <head>
    </head> 
    <!--Internal style sheet-->
    <style>
    .left{
    float:left;
    }
    .right{
    float:right;
    }
    </style>
    <body>
    <div id="wrapper" >
        <div class="left">
            <p class="t0">lorum itsum left</p>
        </div>
        <div class="right">
            <p class="t0">lorum itsum right</p>
        </div>
    </div>
    </body>
    </html>
Additional note: If you want to adjust the size of left and right div then use width in style sheet. Refer the updated style sheet below. I made left div width to 80% of the screen width and right width to 20%.(total should be 100%). Adjust accordingly.Background color used to set the background color of the div.
.left{
float:left;
background-color:powderblue;
width:80%;
}
.right{
float:right;
width:20%;
background-color:yellow;
}