how can i replace default category to my own category >?

Hi,

When a demo is installed with content there will be demo posts and categories imported. To display your own content in pages (blocks, grids etc) edit the page with the composer
– https://tagdiv.com/tagdiv-composer-page-builder-basics/
Each block or grid can be customized to display your own content
– https://forum.tagdiv.com/block-settings-guide/

In the screenshot you mention that is the ajax menu, blocks can display it. You can choose to display categories, tags, authors or a popular filter – http://prntscr.com/n6v9jd

So for example when enabled and set by categories, by default all the categories you have will be shown. However the categories that appear there can be controlled by entering specific category IDs
– https://www.screencast.com/t/yMwVWBaqbJ
– https://www.screencast.com/t/BfB3rIVBUv
– https://www.screencast.com/t/cTa5OBBkt
The same for authors and tags.

Please let me know if you have more questions.
Thanks