Hello @kbyportmelb and welcome. There are loads of threads on here (too many for me to copy but have chosen a good one for you to start you off)
And then use the spyglass at the top of the page to find more plus HO members will add comments am sure.
We’re experienced sitters not owners (but do own our own home) - make sure you read the application throughly, specify perhaps that you want certain things in your sitter like experience with behaviour issues etc & a certain number of reviews (as you’ve had a bad experience before) look at their other reviews, do a video call, trust your gut.
As a random aside, are you in Port Melbourne, Vic as have old Barwon Heads friends who lived there for years!
Best of luck 