Yes of course the business card template is correct at 3.5"W x 2"h. There are multiple artboards depending on if you choose a folded or vertical, so delete the other artboards.
If your color goes to the edge of your design, you will want to add bleed (standard is 1/8" on each of 4 sides, but some printers may go less to save paper).
Check your printers website for templates, as if you use their template, you will make their job easier and get better service.
