SurrealDB has ten official SDKs. Each speaks the same RPC protocol over WebSocket or HTTP, so the concepts carry between them: connect, select a namespace and database, sign in, then query. What differs is the idiom - types, async model and error handling follow the host language.
Every SDK page opens with a quickstart that gets you connected, and continues into a reference for each method.
Community SDKs cover further languages, and the Expo and React Native guides cover mobile.
Choosing between the interfaces
An SDK is the usual way in, but it is not the only one. The RPC protocol keeps one connection open and is what the SDKs use themselves, so it is the interface that supports live queries. The HTTP REST API opens a connection per request and suits environments where holding a socket is awkward. The CLI covers import, export and one-off queries.