The Cherenkov Telescope Array (CTA) is the next-generation atmospheric Cherenkov gamma-ray observatory. CTA will be deployed as two installations, one in the northern and the other in the southern hemisphere, containing dozens of telescopes of different sizes and designs, used for covering different energy domains. These telescopes interact with other systems (e.g. central observation execution software, infrastructure, etc.) fundamental for the Observatory operations. We have created a set of about 70 use cases (UCs) that describe the different type of interactions of a generic CTA telescope with its surrounding systems. These UCs describe different scenarios, from normal night operations to reactions to hazardous situations. Thanks to these UCs we can refine requirements, identify interfaces and specify the expected behaviour of the telescopes. The UCs are also an important ingredient to prepare the test cases for the integration and validation process of the telescopes into the CTA Observatory. This contribution summarises the methodology and tooling we have followed to identify and specify these UCs, as well as the main obtained results.