Step 16 - Install the hive-top feeder
Orient the hive-top feeder so the feeding area is toward the front of the hive, if the feeder is designed like the one shown in the top picture.  If your feeder has side access like the BeeCARE Dual-access Hive-top Feeder (2nd picture), the orientation doesn't matter.  Place the front edge of the feeder on top of the back edge of the brood box and slowly slide the feeder toward the front of the brood box.

Step 17 - Fill the hive-top feeder with syrup
Fill your hive-top feeder with at least a gallon of sugar syrup.  Use your bee brush to keep the bees away from the syrup and off the feeder while you are filling it.  Be careful to fill slowly enough to avoid spilling syrup over the edges.  Syrup on hive surfaces is a bad thing, as it encourages other bees to rob the hive, increases the bees' aggression (i.e. desire to sting), and attracts ants, wasps and beetles.

Tip: Tape the inner cover to the top of the empty hive-top feeder ahead of time and pour the sugar syrup through the center hole in the inner cover after the feeder is placed on the hive.  Then you can remove the inner cover immediately before placing the top cover on the hive.  This minimizes the number of bees that get into the syrup while you are filling the feeder.

Step 18 - Close it up -- you're done for now!
Place the telescoping top cover on top of the hive-top feeder and ensure that it's properly seated on the feeder on all four sides.  Place rocks or bricks on the cover to keep varmints such as raccoons out of the hive.

You're finished for a week!  Resist the temptation to open the hive before a week is out, as this will disturb the new colony's progress in building up their honeycomb, colony population, and honey and pollen stores.

See also: Revisiting the New Hive