For examples of the calls and what might be returned, refer to Best Practice and Use Case Examples. Typically, the options that are returned will be presented at the end of the checkout process in some sort of clickable grid (depending on what is selected as the Return Type). However, the options can be presented at different stages of the consumer journey, and in varying formats.
Your Metapack implementation consultant may be able to advise you on ways in which you can lay out the different options.
You should consult your front end developers to ensure that the JSON responses containing the options are parsed appropriately so that they are rendered as required for presentation at each required stage of the consumer journey:
Remember that the options will need localising from English (UK) into the appropriate languages, date formats, etc. for your overseas consumers.