Guitar Hero: Warriors of Rock

Start a Basic tutorial, skip all the blah blah using the A button, then play the first basic guitar lesson, just holding A and strumming in time.
To be safe make sure you have calibrated before you attempt this one :)

From the main menu select Play and then Training.

In the Training menu select tutorials, depending on what instrument you are using select it and then the basic tutorial.

During tutorials you can press A/Green to skip the talking.

The basic guitar tutorial is particularly easy as its just strumming the green fret, there's a beginning part which just involves talking, then a bit more talking before the notes start.

You must hit every note and not over strum.

Here's a video of the guitar tutorial.