Administrators can create a pairing instantly between two users.
Navigate to Office Settings>Executive Assistant. Under that section, click the + icon and designate an Executive by typing in a name.
The field should auto-complete against your list of Dialpad users. Do the same for designating an Assistant in the next field.
Keep in mind that you won't be able to set up reciprocal pairings.
Let's say that Bob is John's Assistant. Since Bob assists John (and can answer + make calls on his behalf), Bob can't add John as his Executive since it will affect the way calls are handled.
Dialpad Tip: You can add up to 25 Executive Assistant pairings.