Welcome to the forum.
It sounds like you have created a Title, and have placed it over a Clip. Is that correct?
If so, just Dbl-click on that Title (it is easy to see in the Timeline View Mode, so if you are in Sceneline View Mode, just switch), and it will open in Titler.Use the Selection Tool (the arrow) to click on the "Add Text", and you will get a Bounding Box around it. You can Delete it, or can replace "Add Text" with whatever you want.
As Bill says, the key is to work in Timeline mode rather than Sceneline.
Yes, Sceneline is good for initial layout, but switching over to Timeline View Mode allows so much more power for many things.