The idea is to get everything in place as quickly as possible. Then the course builder will tweak the obstacles, in running order, to ensure that the flow is comparable to that on the course map. Failure to look at the course in performance order will result in missing something obvious. This can all be accomplished quickly. It's time to chase away all of the course builders except 3 or 4.
Someone has to put up the numbers.
The judge should be summoned at this time to tweak the course. This commits the judge to stop tweaking. Also, lay the jump bars perpendicular to the jump standards so that the judge can immediately measure the course when he's satisfied that everything is set. Course building time should take no more than 15 minutes. Getting the judge to move is often the wildcard.