If you are not familiar with the OGC instances (WMS, WCS. WMTS, WFS), you can read the documentation here and watch our OGC webinar, to learn all about OGC in Sentinel Hub.
Our OGC webinar has a section dedicated to QGIS, where you will learn how to import OGC layers with manual import, install QGIS plugin and how to use QGIS plugin to make requests and download images.