You can't! With a datasheet form you get what Access gives you; data fields
in rows! You can do all you want in Design View, add command buttons, labels,
comboboxes, etc, format fields with color and so forth, but they're not going
to show up when the form is run!

The best you can do is make your form a Continuous form and format it to look
like a datasheet form, then you can add things to it. If you only want one
button, rather than one in each record, put it in the header.