You need to use the anatomy of the facets of the greater tuberosity to help you. The greater tuberosity has 3 facets, Horizontal, Oblique and Vertical.
Supraspinatus inserts onto the horizontal facet particularly the anterior 2/3rds.
Infraspinatus inserts onto the Oblique Facet and a variable amount onto the posterior 1/3rd of the horizontal facet.
The posterior 1/3rd of the horizontal facet is the region where the fibres of SST and IST mix, the conjoint tendon area.
See the video to have a full explanation of it.