To generate client code to access the API for your particular development language
You will now see the API definition in the left hand pane and a graphical version in the right hand pane. Now choose generate client, select your development language and a file will be generated for you containing complete source code to access the GeoAR.it endpoints.
If you're a Visual Studio developer you can right click on your project and choose Add..Service reference and click Add under the OpenApi, gPRC section. Select OpenApi..Url, paste https://geoar.it/swagger/v1/swagger.json into the input box and click Finish. To view the generated C# code right click on your project and choose Add..Service and the click on the ... next to 'Configured' and Choose 'View generated code'.