hbic Kindly check now. Ref: Screenshot
Here is the main step performed to get the similar JA Builder page layout as sought by you :
1) Had changed the specific menu item type to Menu item type > Articles > Category Blog
and selected category which you may change accordingly and configure menu item > blog layout
to get the appearence as preferred
For in-depth tutorial, Visit this link
You can now edit specific JA Builder page as per documentation excerpt by clicking on "Pen" icon which appears at top-left corner after being logged in and you will be presented with content blocks like seen from visual- documentation in which :
1) You can change modules to reflect from specific module position in sidebar block.
2) Main Content block is already rendering the Article : Category blog layout
Also, Ensure to have more articles added for specific category assigned