When and how do I book the Medical for my visa?

Once your nomination has been lodged, you can apply for your visa as well.

For that, need to log in/sign up to a VEVO account on the Immigration website. https://online.immi.gov.au/lusc/login

Once you log in, go to Health option, which is number 6. Fill out all the related information details for the main applicant and dependant as well. (You will need TRN to complete that form which you can ask to immi agent) Then, you will get Hap ID. and receipt as well. For more detail, please follow below website. https://immi.homeaffairs.gov.au/help-support/tools/emedical/emedical-client

Then, you need to search for nearest clinic where you go for health check up.  Make sure, you bring Hap ID document with you. Once your health check up is complete, Your result will be directly updated on your VEVO account.