Button next to dropdown and layout

Button next to dropdown and layout

Question 1: How can I add a button next to every dropdown? I want that button to show a hidden field when I click it.

Question 2: Is there a way I can create a model window for a multiline text. If my question 1 is possible then I want it to open the model window or pop up with the multiline textbox.

Question 3: Can I create a three column layout?

Thanks.