itemMatrixID's vs itemAttributeSetID

tiegos

if i do a json request for products, i finde products (with different measures for ex.) whith the same itemMatrixID's

if i do a request for matrices and look for that specific itemMatrixId, i find info i need on this matrix, like a description and all values in this matrix

but how can i connect this products to one measure in a matrix?

is it through the itemAttributeSetID? and wich id the url for this json

or is there another way i don't see?

tiegos

i saw that itemAttributeSetID is for the kind of matrix

but still do not find how to identify a product with a matrix