Avery's site in Canada (avery.ca) also offers templates for standard size business cards. Besides three 'text on white space' versions, the site shows over 1200 designs for cards in single side or front and back styles.
The cards are done in a four step process:

The Customize step is where you edit the template content and design to fit your ideas and needs. The editing is teo stage:
Edit All, which shows an enlarged version of the card design. Changes you make here apply to ALL ten cards on a sheet.
Edit One accepts similar edits to images and text, but the edit applies only to a single card on the sheet of 10.
The fifth step (actually an extension of the fourth) is a logical and essential one:

Note that you can go back and edit your design, then return to Preview mode to review the changes and see this page again.
If you like the result, but want to print it at home, click the "Or, print this myself" item.
If you want Avery to print the cards, then ship them to you, I think "I Approve My Design" will take you there.
I suspect the process is much the same in the US and on other Avery sites elsewhere in the world.
Regards,
Barry
PS: avery.ca is undergoing maintenance tonight. The site will be closed for two hours starting 61/2 hours from the time of this posting.
B.