I wish to start using paid resources but do not know where/how to do it.
You will first need to verify your account with a valid credit card.
You can also experiment with the pricing of your selections by using our interactive pricing page. You can see the different options available for the amount and type of dynos, add-ons, databases and support levels available with Heroku. As you select from each of these options in the pricing page, you will see the top-right area update with the pricing estimate based on your selections.
Note that if you accidentally select the wrong dyno or plan size, you can always downgrade immediately. All credit card billing on Heroku is pro-rated to the second - for example, a "$25/month" item is approximately $0.00001/second. For more details, please see our Usage & Billing documentation.