https://developer.apple.com/library/prerelease/content/referencelibrary/GettingStarted/DevelopiOSAppsSwift/index.html#//apple_ref/doc/uid/TP40015214-CH2-SW1

Jump Right In、、、すぐ飛び込め、、、意訳するなら「すぐやれ」でしょうか。

IMPORTANT

This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.

preliminary 前置きの、準備の、