1. To put an item in your cart, you can either click on the "Buy now" button

OR

when you're viewing the product info for a specific product, clicking "ADD to Cart" button will have the same effect

 

2. After adding an item to the cart, the following screen will appear :

Clicking on "checkout" will send you to the payment screen.

 

3.If you haven't login with your account, it'll ask you to login to continue. After logging in, the following screen will appear :

4. Since paypal is the only option to purphase the products, press the "continue" button on the picture below to continue

5. Clicking "confirm order" like the screenshot below will take you to the Paypal login screen. After successfully logging in to Paypal, the following screen similar to this one will appear :

 

6. You'll then have a screen saying you've successfully pay the payment. DO NOT CLOSE THE WINDOW! It'll then redirect you back to the Mercado shop in 10 seconds to complete one final step.

 

7. To check the status of your order, click on "My account", and click on the button "view"

Items that have been delivered will have the word "Delivered" instead of "Processing"