Unresolved variable or type Vue

Hi Everyone,

I started learning Vue.js and I am using WebStorm as my editor.

I added following line to index.html file, right on top of closing body tag:

<script src="https://unpkg.com/vue@next" defer></script>
<script src="app.js" defer></script>

I also clicked on the light bubble thing and downloaded the library.

Now in the app.js, I have following code:

Vue.createApp({
    data() {
        return {
            myData: 'Text here'
        };
    }
}).mount("#user-goal");

Now there are 3 problems with this setup.

1-) in line

Vue.createApp({

Vue is underlined yellow and when I hover the mouse over it, I get "Unresolved variable or type Vue" error.

2-) In the same line above, the autocomplete does not work when i start typing "Vue.crea....". How can I make sure that the auto complete actually parses and shows suggestions for functions that belong to Vue.

3-) In the following line:

}).mount("#user-goal");

mount is underlined and I see "Unresolved function or method mount()"

 FYI, I tried right clicking on the file and selecting "Uses JavaScript Library" then "Vue". It is already selected and marked gray. So I cant make any changes there.