The Smelling Bottles are a super popular Montessori Sensorial exercise for children in the Primary class.
For younger children, you can use scents and language in an overall experience without any special setup. Select something like cinnamon bark, hold it and sniff it. Now hand it to your child to sniff. Say that it is cinnamon. Put the cinnamon in a small jar with a lid on a low shelf in his or her home classroom or bedroom, so that it can be taken out and enjoyed. Add a new scent the next day. A vanilla bean, nutmeg, chili pepper, basil leaves, dried orange peels, and other different scent objects make wonderful additions to this collection.