How can i add navigation in questions (next/prev question) and also a share buttons, as on your website (in the widget)?

Hi Semion,
 
– To show the sharing buttons on single question page, you need to edit the sidebar-single.php file in plugins/dw-question-answer/inc/templates folder. So open up the file and find this code (somewhere at the bottom of the file):
 

<?php do_action( 'dwqa_question_meta' ) ?>

Then add the following code right above it:
 

<li class="share">Share
 <span class="pull-right">
 <div class="share-btn">
 <a href="https://twitter.com/share" class="twitter-share-button" data-text="@" data-url="<?php the_permalink(); ?>" data-text="<?php the_title(); ?>" data-via="designwall_com" data-related="designwall_com" data-hashtags="wordpress" data-count="none">Tweet</a>
 <script>!function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="https://platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs");</script>
 </div>
 <div class="share-btn" style="width: 33px !important;">
 <div class="g-plusone" data-size="medium" data-annotation="inline"></div>
 <script type="text/javascript">
 (function() {
 var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true;
 po.src = 'https://apis.google.com/js/platform.js';
 var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s);
 })();
 </script>
 </div>
 <div class="share-btn">
 <iframe src="//www.facebook.com/plugins/like.php?href=<?php the_permalink(); ?>&amp;width&amp;layout=button_count&amp;action=like&amp;show_faces=false&amp;share=false&amp;height=21" scrolling="no" frameborder="0" style="border:none; overflow:hidden; height:21px !important; width: 51px !important;" allowTransparency="true"></iframe>
 </div>
 </span>
</li>

You’ll need a little CSS to style for the sharing buttons, so add this code below to the stylesheet file of your theme:
 

.dwqa-sidebar .share {padding-bottom: 0;height: 21px;}
.dwqa-sidebar .share .pull-right {margin-top: 4px; margin-right: -3px;}
.dwqa-sidebar .share .share-btn {display: inline-block;height: 21px;overflow: hidden;}

– About the navigation questions, if you are comfortable with PHP, you could modify the single-question.php file in plugins/dw-question-answer/inc/templates folder to add Next/Prev buttons in before or after the page.
 
Hope that helps!