Changing the text data in a pre-loaded template

[Heratbreaksoup]

Good evening and thanks for reading a newbie question, and it's probably extremely basic and obvious.

I've downloaded Gimp 2.10.32 because I would like to make my own Blu-ray covers for my collection using a fan template of The Criterion Collection sleeves.  Over the last three weeks, I've slowly been learning about layers and changing the direction of text boxes.  I know that Rome wasn't built in a day. 

But I'm stumped in how to change the pre-loaded data within the template.  This template is pre-loaded with some basic, junk numbers for the back cover information:

2015
75 MINUTES
COLOR
MONAURAL
2:35:1 ASPECT RATIO

These figures seem to come from the "name" / "layer attributes."  When I right-click on the layer that contains this information, I get an option that says "Edit layer attributes."  This gives me a pop-up box where I can change the layer name.  The name of this layer is: 

2015 75 MINUTES COLOR MONAURAL 2.35:1 ASPECT RATIO

But whatever changes I make to that name just change the name of the layer, not the text that appears in the image.  How can I make changes to those figures so that the text of the image reads what I'd like it to?

Thanks in advance.