when most books talk about spells, they tend to be referring to the spoken/written portion of the working. to them, this is the base unit of a magical working. because description is an easy and simple way of using imitation, its a nice bases on which to build a more complex working.
start with an incantation that describes what you want to have happen.
for the next layer of complexity, add a gesture or motion to help emphasis your script. often you can use gesture to help indicate information your mouth is too busy chanting to include, such as direction and location.
the next layer adds physical items or substances to the working. and these tend to fall into one of two categories.
the first is that the item is a prop used to embellish and add nuance to your incantation. often interacting with the words through the logic of simile, analogy and metaphor. in this stage the item doesnt hold any magic itself, it simply serves to help emphasis the message of the incantation.
and then there’s the talismanic side. in this model the spell is point at the object/substance with the intention of embueing it with magical essence which can then be used through the item. in this instance the spell and its energy are directed into the objects, which then house the energy untill they are released, usually through deployment of the item in question. often, the condition for the magic to express itself is linked to the objects mundane use. for instance, an enchanted candle expresses its magic when lit, a knife when sed to cut, insense when burnt, and so on.