And here is a good tutorial: https://www.youtube.com/watch?v=N6ZkLpBrseU
He creates the text matte from 4:35 onward. Only thing that you have to do differently to make it easy, is to create the mask of the matte layer to the area where you want the text to show and then use Alpha Matte instead of Inverted as he does in that video. :)
Hope these tips help!
What I would do, is follow the instructions for scolling credits, but then, after you want the text to show only in a certain part of the screen, use a matte. There are at least three ways: track matte, set matte, preserve transparency. I suggest using a track matte. So create a solid layer above the text layer, create a mask on the solid where you want the text layer to show, add feathering if you want. Then set the text layer to use the matte layer as an Alpha Matte. Now the text will show where the matte layer's mask is, and you can work on the text however you want - you can animate it, etc. There are great tutorials on track mattes on Youtube. :)