This beautiful song is in 5/4 rhythm, which makes the simple steps a little harder to teach and to learn. Although it's not a tango (it's a Bossa Nova), it does have some tango-esque elements. People seem to be tempted to stomp, but it really doesn't suit the music or the mood of the dance
To begin the lesson, I recommend having the students listen to the music and say along with it "One two three four five" so they get the feel of 5/4. There is never a step on beat two, so it's really "One hold three four five". Two different times the music adds one extra beat. Just be ready for it and draw out that pattern to fill the space. The dance can be done in two opposing lines for a nice effect.
GRAPEVINE RIGHT A LITTLE DIFFERENTLY, GRAPEVINE LEFT
1-5
Step right, hold, left behind, step right, touch left
6-10
Step left, hold, right behind, step left, touch right
11-20
Repeat 1-10 as above
1-5
Right step forward, hold, left touch to right, step back on left, right touch together
6-10
Right step back, hold, left touch to right, step forward on left, right touch together
1-5
Right step forward, keep weight on right and pivot ½ to left, change weight to left, right together, weight on left
6-10
Right step forward, keep weight on right and pivot ¼ to left, change weight to left, right together, weight on left
1-5
Right out to the side, drag to left, weight on right, weight on left, weight on right
6-10
Left out to the side, drag to right, weight on left, weight on right, weight on left
1-5
Right cross left, ½ turn to left, weight on right, weight on left, weight on right