It still has to be worked out what Substance is, that is, what one means by the term "Substance" (here -- on this website -- this especially means : what one should mean by the term "substance").
For the time being, the following may be determined :
Substance in the broad sense is the complete Totality, thus including the determinations ('accidents'). Said fifferently : the entire Totality, its genotypical aspect as well as the phenotypical expression of that aspect.
Substance in the strict sense is the genotypical aspect (the Essence, the Dynamical Law) of the Totality.
Determinations (and thus also properties) are the phenotypical aspect of the Totality, they are the phenotypical expression of the Essence. Or said in yet another way : they are the concretum (of the [central] principle, the Essence). Scholastically we can say that determinations have Substance as (their) subject.