How do I delete part of a single layer?

I’m terribly sorry if this is a question that has been asked before, but I’m trying to edit an existing image and part of that involves deleting a section of one layer. However, each time I try, it seems to hit all layers in the picture, including the background. Is there any way to isolate a layer so that any edits made only affect that layer?

How do you do it?

Personally I do it by selecting parts of the active layer with the selection tool and then just hit ctr+x.

I’ll try that–I was using the delete key after selecting an area, as that was what I was used to, but adapting to new software means adapting to a new control scheme.

I believe the delete key fills the selection with the foreground color and the backspace key with the background color.

There might be an actual delete content key but I find that cutting it out with ctrl-x works just as well.

The main Edit menu drop down tell you the keyboard shortcuts for ‘Clear’, ‘Fill With Foreground Colour’ and ‘Fill with Background Colour’. The Del key does ‘Clear’ by default so that should not have affected other layers in your document, unless you’re using not-Normal layer blending modes or alpha inheritance in some way.
You can change them in Settings → Configure Krita → Keyboard Shortcuts.

It worked! Thank you for the help!