Also to be clear, the design is: one header on top, two column layout for buttons and input fields on left and right. after that full width two buttons and on the bottom its need to be full width text area.

Here example of my code how is organize the structure of the code:

2. <div data-role="page">
3. 
   
4.     <div data-role="header" data-theme="none"> 
5.         <h1 class="headerTitle">Calculate site heading</h1> 
6.     </div><!-- /header -->
7. 
   
8.     <div data-role="content"> 
9.     <div class="ui-grid-b">
10.         <div class="ui-block-a">
11.             <label for="startPoint" class="startPoint">Start Point</label> 
12.           <input class="latitude" name="latitude" type="text" value="Lat:" />
13.           <input class="longitude" name="longitude" type="text" value="Long:" />
14.                      <input type="button" value="Current Location" data-theme="b" />
15.             </div>
16.       <div class="ui-block-b" style="float:right;">
17.             <label for="startPoint" class="startPoint">End Point</label> 
18.           <input class="latitude" name="latitude" type="text" value="Lat:" />
19.           <input class="longitude" name="longitude" type="text" value="Long:" />
20.                     <input class="currentLocation" type="button" value="Current Location" data-theme="b" />
21.             </div>
22.             <div class="ui-block-c"></div>
23.     </div>
24.         <input class="calculate" type="button" value="Calculate" data-theme="b" />
25.         <input class="reverse" type="button" value="Reverse" data-theme="b" />
26.         <div style="width:100%;">
27.           <textarea> Nice studio for renovation </textarea> 
28.         </div>
29.     </div><!-- /content -->            
30. </div><!-- /page -->