Need Help with creating a component

Scenario:
I created a login page, but in the dashboard, I need to create a dropdown where if I selected an option it needs to populate a dropdown box under it with testcases available for that selected option

I will attach a screenshot I have a basic idea but I need assistance putting in the form of code

Let’s call the first dropdown dropdownA, and the second dropdown, dropdownB

I would make an object whose keys are the options available in dropdownA, and whose values are an array of the options that will be available in the corresponding dropdownB.

Thanks but my main issue was I couldn’t figure out how to add check boxes to the dropdown

You didn’t mention checkboxes at all.

sorry for the confusion it might be hard to see from the screenshot and also how can make the dropdown box align under each other

Thank you very much for the help
dropdown