First, you'll need to download the current state of your store's site. For that, go to Administration > Site Development > Code Deployment. enter the active version and download it. Then unzip the .zip file you downloaded.

Then, download the latest version of "int_mercadopago", the Mercado Pago integrator, from Salesforce Partner Marketplace.

Lastly, unzip the .zip file and place its contents in the same folder on the store site. In this way, the "int_mercadopago" folder must be at the same level as the "app_storefront_base" folder.

Done! You have already stored the Mercado Pago cartridge on your store site.