You might choose to stay indoors, using scents you bring including spices, perfumes, etc.
A blindfold will help focus attention on the scents.
Walk the walk — Walk along the path before taking anyone along it to make sure it is safe.
Explain — Explain that you will be describing the walk in smells / scents.
Walk outdoors — Take your walk and see what you can smell. They might include:
- Plants / flowers
- Trees / fruit
- Soil / sand
- Decomposing wood / leaves
- Dead / decomposing animals
- Stagnant water
- Worms / insects
Walk indoors — Bring in nature or use man-made scents to experience, including:
- Spices / herbs