First - go to WPBakery Page Builder > Role Manager and under the user roles, choose the post type Custom and check the post type you want to use the WPBakery Page Builder (nasa_block)
Simply go to Static Blocks > Edit Size Guide
You can use this HTML to create the initial Size guide and edit it to what you want
If your site uses Elementor: go to Theme Options > Elementor Header & Footer Builder > Add New or Edit Size Guide (Template: Custom Block).
You can download this JSON file to import the "Size Guide" by "Elementor Header & Footer Builder" plugin here
How to import JSON file:
In addition, you can override the Size Guide for Root Category Product (Parent=0)
All the products in this category will display this size guide
Size Guide for each product (High priority)
Please navigate to Products→Edit Product→ In this Product Tab choose Additional → Additional → Choose the Size Guide table that you created in the Static Block