First you should take a look at some of the magento 2 resources available (Can anyone suggest more technical resources for Magento 2?) or http://devdocs.magento.com/
In terms of adding a block, I'm assuming through the CMS you can use the following:
{{block class="Xanka\\Slider\\Block\\Slideshow" block_id="block_identifier" template="slideshow.phtml"}}
