How to search Amazon API for a book by title and get JSON response

I signed up for AWS and am trying to play around with their API.

What I want to do is use their REST API to search for books via a book title and get the results back in a JSON string.

I think this is the correct method:

http://ift.tt/1O6KLyG

And the example they provide is:

http://ift.tt/1f5d9Nk? 
  Service=AWSECommerceService
  &Operation=ItemSearch
  &ResponseGroup=Small
  &SearchIndex=Music
  &Title=Blue
  &AWSAccessKeyId=[Your_AWSAccessKeyID]
  &AssociateTag=[Your_AssociateTag]
  &Timestamp=[YYYY-MM-DDThh:mm:ssZ]
  &Signature=[Request_Signature]

I am a little confused about the parameters...

AWSAccessKeyId = This I was able to generate by clicking going in the console and on the top right clicking on My Name->Security Credentials -> Access Keys.

AssociateTag - What is this?

Timestamp - I have to pass in a timestamp? Why?

Signature - What is this?

And finally I want to only search books. Does this mean that SearchIndex should be set to Books?

Thanks for helping out a noob!