I'm very new to photoshop.
I wanted to transform a layer like the one in the below snapshot.
The layer is not rotated, but the black background with your screenshot is here rotated.
I actually got this from a Macbook Air mock up where I wanted to fit in my screenshot and I'm actually unable to rotate and fit it exactly. I tried rotating the content using the Transform control but it didn't help.
Original mock up here.
Thanks in advance.
You can either select the part you need to transform, then edit it. Or you can use distort, which is under edit > transform > distort.
Hope this helps. If you have a question, or if you don't understand something, feel free to ask.