Justine,
A drop-down list is called a Combobox. In design view of the form,
check to see if the Toolbox is visible. If not, you can enable it from
the standard toolbar, via the icon with the hammer and spanner, or else
via the View menu. On the Toolbox, there is a Combobox icon. Click the
icon on the toolbox, and then click on the form design and a combobox
will be placed there. If the Wizard icon (looks like a magic wand) on
the toolbox is enabled, the act of placing a new combobox on the form
will trigger a wizard process to assist with setting up the combobox.
Some people like this, and others find it confusing. Otherwise, you
will need to learn how to use the Property sheet for the combobox to
make it behave as you want.