When it opens up the new layer, can you still put the text on it?
If so, you are doing nothing wrong. You want everything on it's own layer. It makes it much easier to move things around to where you want them.
I hope I understood your question and this helps!
Oh, I think I did misunderstand - I think this answer may be better.
If you have already made the text layer, in order to change it do this...
select the text layer (with the top left arrow looking tool highlighted)
after selecting the layer (when the box is around the text), right click on the box and choose edit text. Then everything in the box will highlight and you can change as you wish.