Must be ticked to select the dropdown

I create a dropdown box like the picture below, i want my member must be ticked to select the dropdown.
How can i do that?

https://www.wix.com/corvid/reference/$w.Checkbox.html
https://www.wix.com/corvid/reference/$w.Dropdown.html
https://www.wix.com/corvid/forum/community-discussion/multiple-inputs-enable-and-disable-a-button