Help with dropdown

Select the dropdown and go to Properties panel on the right of your screen. Select the event click and hit enter. Something like this will come up in the code editor.

$w("#dropdownID").onClick( (event, $w) => { 
 // The dropdown has been clicked
} );

Then add a box to your page with the information inside you want. Select it, go to properties panel and make it collapsed by default.

Then add the below code into your above click event like this

$w("#dropdownID").onClick( (event, $w) => { 
    // The dropdown has been clicked 
    $w("#myBOXElement").expand();
} );

Then the box will expand and show the info inside.