How to obtain the portal vertices coordinates of an icosahedral virus

Hi all,
Recently I’ve processed a dataset of an icosahedral virus, and reached an overall resolution of 3A with I symmetry applied for the capsid. Then I tried to go on processing with the portal reconstruction. I know the next thing is to define the coordinates of the 12 vertices then re-extract those sub-particles and do the localized classification to find the class showing portal density. Does anyone have any experience or detailed steps to do this in cryoSPARC?

Thanks.

Liz