The "parameters" like ClientID and ProtocolVersion are HTTP Headers hence you need to pass them a little bit differently.
Add a HTTP Header Manager as a child of your HTTP Request and configure it to send at least "Content-Type" header having the value of "application/json". I believe that you should also add other headers like "ClientId", "ProtocolVersion", "PlatformType", etc.
For HTTP Request itself:
1. Change method to POST
2. Remove everything from "Parameters"
3. Switch to "Post Body" tab
4. Paste your JSON payload there
5. Configure other fields as required (Server Name, Port, Path, etc.)