I always say get the fundamentals right and your Tai Chi will be much more pleasant and successful. Tai Chi walk is one of the most important part you need to learn really well in your early stages. The majority of forms are based on this and hence really important to get this one right. See above an excellent video and below for detailed instructions.

TAI CHI WALKING (FORWARD)

1. Stand with feet together
2. Turn left toe past 45° and turn the body in the same direction as the toe.
3. Transfer your weight to the left foot.
4. Peel the right foot off the ground and draw it in toward the left foot. Don􀍛t rise up as you bring the foot in.
5. Turn the waist to the left corner and step out with the right heel.
6. Transfer weight forward with the right toe facing forward. As you do, kick out with the left heel so it settles at 45° and turn the waist toward the front. You should now be in a classic right bow stance.
7. Sit back and turn right toe past 45° and turn the body in the same direction as the toe.
8. Transfer your weight forward to the right foot
9. Peel the left foot off the ground and draw it in toward the right foot, still facing in the direction of the right toe.
10. Turn the waist to the right corner and step out with the left heel to the left corner.
11. Turn the left toe to the front and start to transfer weight forward and as you do, kick out with the right heel so it settles at 45° and turn the waist toward the front. You should now be in a classic left bow stance.
12. Sit back and turn left toe past 45° and turn the body in the same direction as the toe.
13. Transfer your weight forward to the left foot
14. Peel the right foot off the ground and draw it in toward the left foot. Don􀍛t rise up as you bring the foot in.
15. Turn the waist to the left corner and step out with the right heel.
16. Transfer weight forward with the right toe facing forward. As you do, kick out with the left heel so it settles at 45° and turn the waist toward the front. You should now be in a classic right bow stance.
17. Continue repeating steps 4 through to 14.

TAI CHI WALKING (BACKWARD)

1. Stand with feet together
2. Step back with the right toe to the back right corner, waist to the left corner.
3. Once the right toe is positioned, flatten the right foot, turning the waist to the front, ensuring that the right foot is at a 45° angle.
4. Transfer the weight back and pivot on the left toe, so the left toe is facing the front (a left sitting stance). At the same time turn the waist to the right.
5. Lift the left foot and step back to the left corner.
6. Once the left toe is positioned, platen the left foot, turning the waist to the front, ensuring that the left foot is at a 45° angle.
7. Transfer the weight back and pivot on the right toe, so the right toe is facing the front (a right sitting stance). At the same time turn the waist to the left.
8. Continue repeating steps 2 through to 7.