Hello anonymous user Thanks for posting this query on this forum!
Have you tried the IOTCentral application creation and then you may be able to see the generic device templates to get started.
RaspberryPi has no capability on its own to connect to IoT Central, you may want to add your sensors and readers to the RaspberryPi to make it a capable Interface, then only you can communicate with IoT Central. You can start with your own custom IoT Central application and build accordingly. I would recommend to follow the below 2 documents for this.
Create a device template from scratch
Create your first Azure IoT Central app
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