Those errors come from your linter (probably eslint) which is a tool designed to ensure consistence and code quality : in your case it mainly complains about declared variables that are not used anywhere else in your code and $
being undefined (I guess you're trying to use jquery which you should not be doing in a vue project anyway)
On the images you posted you have all necessary infos : the title of each block tells you in which file the error is (for example App.vue
in the first image) and then you have line/column to locate precisely where you need to adjust :)
Note that you can configure your linter (what should be error/warning/skipped out) overwriting (or creating if it doesn't exist) a config file at the root of your project (if you use eslint for example, you can create a .eslintrc
file). See the config part of the official doc