"jump in" means: to say something about a subject that another person is already talking about , to join a conversation
I understand the meaning of it.
in the next chapters we will go deeper into both syntaxes with many more examples. Jumping right in, a simple XPath string we could write in Python is given here ...
I guess "Jumping in" is the gerund of "jump in". I don't understand the meaning of it. Do they pretty much mean the same thing?