Welcome to the forum!
It's probably better to learn how to edit paths, than use the Eraser tool, to be honest. It doesn't really work on lines/paths, and otherwise I find that tool quite buggy myself. I much prefer to edit paths with the Node tool. Or sometimes the path operations (booleans) can be helpful.
You're welcome to share an SVG file, and explain what you're having trouble with. Then we can give you some resources to learn whatever you need to learn. Or depending on the issue, we might just show you directly how to do something.