The best website for info is on the VHRR (Victorian Historic Racing Register) website. There will be a full list of events, classes, timetables, drivers entered plus the PR and media info.
Here is the link for the event, although sadly only last years info is present, with a promise of updates to come. It gives an idea of the info on there though (2018 meeting.) Plenty of other links on the page to general info of the VHRR, contact info by class/category, galleries of all VHRR events (several hundred images of this years March Historic / classic meeting. )
https://vhrr.com/wp/phillip-island/
It is a fabulous meeting. Very sociable. I will be there .... my highlight of the motor sport year in preference to the closely following Grand Prix.