Setting up the 'screen' with the L button

I've read online and I think in the Prima guide that you can setup a screen play using the L button and a certain passing combination.

Can someone explain how this is done?

For example, say the Denver Nuggets are coming down court with Carmelo Anthony having poseession of the ball. How would he be able to setup a screen play back to himself or someone else?

Thanks in advance!

I know I can call a screen play with the Playcalling button (the d-pad in my controller), but other than that, I have no idea.

Well, inside the Prima guide ...

And from reading the INFO at IGN.com for the game, you can use the L button and somehow create a screen play.

I haven't figured it out yet.