To assemble the harness pieces to the reindeer, I started at the back to make it easier. The back deer (2 rows so you have to do this two times) have the harness that flattens out at the end (see first photo). All other deer in front of the back two have harnesses that are curved all the way to the end.

Line the harness up with the neck as shown in the photo. Glue generously for strong hold.

Do the same thing to the next reindeer and then place the pointed tip at the end of the harness into the notch on the collar of the previous deer. Glue in place. Repeat this until you have 4 deer assembled and glued together. You'll want to complete the whole first side before flipping over and placing the harness on the other side.

Flip this row of deer over and place the harnesses on the opposite side being careful to line them up with the first side. Once you complete this, repeat on the second row of reindeer.

Note that the antlers can be fragile depending upon your wood so handle with care.