And do you have a specific question?
What version of FileMaker are you using?
Sorry if i was unclear. Im using FM 13 Pro Im wondering what steps i have to take to get the desired drop-down function as shown in the image above.
You don't actually need a button, though you can set up a PopOver button (New in FileMaker 13) if you want.
You simply need to place a field on the layout and then use the Inspector's data tab to format the field as either a pop up menu or a drop down list. There are controls in the data tab that let you either select an existing value list for the list of values you want to appear or to create a new value list. Value lists can be based on a custom list of values that you enter as part of the value list definition or you can set them up to use values from a field in one of the tables in your database.