Shopify Ajaxify Product filtering on collection page -

i want add shopify ajaxify product filtering on collection page, https://bc-sf-filter-demo-1.myshopify.com/collections/tops without third app. can't find documentation on it.

can give me thought or helpful resource manually?

there number of shopify apps provide type of search functionality. in case app: https://apps.shopify.com/product-filter-search