So I picked up my bike from the dealer today and had to take the front wheel off to get it in my trunk. Not thinking I just popped the wheel off without examining how it was put on. The wheel is attached with a simple nut and washer, no quick release etc. How should the wheel be secured? Nut --> Fork --> Washer or Nut --> Washer --> Fork. Sorry for the newbish question but I can't remember how it was attached.

Well....

If everything is good and healthy - i.e. no strange mishaps in its past - the washer should go between the dropout and the nut, protecting the dropout from the wear that the turning nut would otherwise cause when it makes contact with the dropout.

But if someone has been playing around with the cones and the over-locknut-distance, or maybe tweaked the fork a bit, anything is possible. The "proper" way to deal with sucha situation would have been to stick any washer used for that purpose inside the locknut, but kludges are common.

Since it's a new bike, I'll assume the hub spacing is correct and the washers go outside the fork dropouts and directly under the nuts. Some bikes use tabbed washers and have mating slots in the fork that the tabs go into to act like "lawyers lips" on qr hubs. That is they act as wheel retainers if the nuts get a bit loose.