Create a class for Visual Composer Grid2

I need to create a class that, when placed in a Visual Composer Grid that currently brings Woocommerce products of a certain category to the carousel, will do the following: 1. Will check the amount of people that have currently purchased that product.n (ex. 25) 2. Will check the amount of product available for sale originally (ex. 360) 3. Will calculate current percentage (ex, 25/360 = .069444 so its 6.9%) 4. Will compare that percent with the percent on the product custom field named "Porciento para establecer como cerrado". 5. If the current percent is equal or bigger than the percent on the product custom field named "Porciento para establecer como cerrado", then allow the product to be displayed.