The two ends of your light strand
look like this:
The large transformer plug
goes into the wall outlet.
To plug multiple strands
end to end, the
transformer is only needed
at the last strand that goes
into the wall outlet. To
disconnect the transformer
from the strand, simply
unscrew it at the base as
shown.
Unscrew the coupler from
the threading. Pull strand
from transformer.
Now the two ends of your light
strand look like this:
Connect the two ends together.
Slide the coupler over the threading
and screw it back on.
The very last strand that goes into the
wall outlet will need the transformer.