Yes if you have the transaction no. and if you had paid the fee, that means you had lodged your application.
Wait until they send you an email, telling you the name of the case officer, additional info they are looking for as well as their request to you for a health check and police check. You cannot do the police check without tge letter.
Actually you can start to proceed your health check with the transaction no. but i think there is no such hurry to start up the health check so earlt given that you can book the health check quite easily. Also, the earlier the health check is done, the earlier you need to go oz and validate your visa once it is granted. Meanwhile you can research whick medical center is closer to you or book a later date for checking.