You can "add" an unbound combo box to your form, using the tools wizard. You bind it to a data set thusly: In the combo box properties window under the data tab, Select table/query for Row Source Type. Click Row Source and then click the ellipsis (...) Add the table to the QBE grid that you want to use to populate your combo box. Drag the fields you want to include in your combo box--usually one or two--into the query. Include the key field. Close that query and return to your form.
In the combo box properties window - Control Source (just above the two above) enter the key field name for the table you used for the query. All you have to do is set your Column Count to the total number fields used in the query and adjust the Column Widths--usually the key field column is set to 0".
If you're adding new info, then you need the event procedures to handle that. Check some of the forums, I am sure it's been posted previously.
Hope I answered your question.
Mary