Hi Youness tallih,
Please note the code lines which you edit in the left-right-main.xml.
There are some wrong points such as </ Header>, </ position>, </ Positions>
The exact code lines are:
<header order="2" id="yt_header">
<positions>
<position width="270px" height="" type="feature"> @ logo </position>
<position width="730px" height="" type="modules"> header3 </position>
<position width="" height="" type="modules"> header1 </position>
<position width="210px" type="modules"> header2 </position>
</positions>
</header>
Thanks
