Class 1 Medical
Essentially it is a whole new medical.
In terms of what is required.. It is age-based, and CASA's website also has a chart which shows pretty clearly the relationship between age and required items. For example, some items are required at the first renewal after your 30th birthday, and then every 5 years thereafter.
CASA website has a list of DAMEs.. get on there, call a few of them in your area. I say call a few as the price varies widely. I called a few in / around Melb CBD / for my renewal yesterday, varies from $250 to $300 including ECG + bloodtest, audiogram an extra $70 at another provider. You might find cheaper out in the 'burbs.
Look for a place which can do all (or as many) of the tests for you at once, to save yourself time going to various appointments all over the place. Typically you will need to go to separate places for the Audiogram and Opthamalogical, I have not found a place that does them at the same place as the medical.. But that doesnt mean they don't exist.