How do you decipher and translate the iOS Swift documentation into this class method?

I'm trying to get used to the documentation but it's a stretch to understand. I can find the related information fine, but deciphering what it means has proved tricky for me. For instance, I'm looking at the dataWithContentsOfURL:options:error documentation which states:

Creates and returns a data object containing the data from the location specified by aURL.

• (id)dataWithContentsOfURL:(NSURL )aURL options (NSDataReadingOptions)mask error:(NSError *)errorPtr

Then the result should be according to the video lesson:

NSData.dataWithContentsOfURL(forecastURL, options: nil, error: nil)

My question is how are you supposed to arrive at this result from the documentation? For example, is the (id) part in the beginning of the example supposed to represent the class NSData in the result? What does the part :(NSURL *)aURL mean? Why is NSURL enclosed in it's own parentheses in the example with an asterisk?

I'm just looking for a little guidance in terms of understanding translation from the documentation in order to navigate uncharted waters on my own. Any help is deeply appreciated!