Here is the step-by-step process on how to upgrade your membership to premium:
From your dashboard, click on the hamburger menu icon (three horizontal lines) in the top left corner, then select Settings from the menu.
In the Settings page, locate and click on the Membership option in the left sidebar.
Select your preferred billing cycle - Monthly or Yearly. Yearly plans often come with a discount. Click Choose Plan to proceed.
Complete the payment form with your details, click Proceed to payment, select Instant payment, and finally click Pay Now to complete your upgrade.

Note: Once your payment is successful, your account will be immediately upgraded to premium and you'll have access to all premium features.