You can certainly use thread but in most use cases, concurrency or parallelism will accomplish the same in a much saner/safer way. (they're wrappers around core.thread anyway).
Don't know of any tutorials about core.thread, about the other two you can find help here : http://ddili.org/ders/d.en/ 

2015-07-16 11:24 GMT+02:00 aki via Digitalmars-d-learn <digitalmars-d-learn@puremagic.com>:
On Thursday, 16 July 2015 at 08:21:26 UTC, maarten van damme wrote:
Have you checked out std.parallelism and std.concurrency?

I know std.concurrency to use spawn. If I cannot use Thread,
I'll implement by spawn. But want to try Thread class because
it seems similar to Java's Thread class.
I don't know std.parallelism. It seems for the different case.

Aki.