The guide outlines a step-by-step process for creating a user interface in Retool to interact with DigitalOcean's Spaces API, allowing users to list, view, and upload files within a Space. It starts by setting up a connection to DigitalOcean Spaces via Retool using a custom S3 endpoint and details how to create a basic UI for listing files in a specified bucket. Users can input the bucket name, triggering queries to display files and metadata in a table format, with options to preview images stored as Base64 data. The guide also explains how to upload files through a file picker component and a custom query, addressing potential CORS issues that may arise during file uploads. The tutorial highlights the flexibility of Retool in customizing UI interactions with Spaces, providing a practical solution for managing data storage efficiently.