Welcome Gina, I too have a frog named Olive! He is a whites green tree frog.
You might want to check the out the care sheet on the forum for your particular frog. This will tell you the proper humidity and temperature for your setup. I kinda remember reading somewhere that it's not good to put them by a window due to temperature changes and stress.
My frogs are still juveniles and I had one die that seemed to have a calcium deficiency, so I dust their crickets with calcium every day and then a few times a week switch it out with a multi-vitamin. Daily spot cleaning (removing poop, wiping glass, cleaning decorations) should keep your tank in good shape for months. Also, make sure you clean food bowls and give fresh treated or spring water daily or every other day. The only time I change the substrate out completely is if it gets too saturated, and that doesn't happen to often.
As far as samonella I am not sure. I know that turtles carry it. They have very sensitive skin and absorb everything through their skin so keep handling them to minimum. If you have to handle them, make sure you wash your hands with unscented soap before and after. You can also use unpowdered latex gloves to handle them.
Do you have pictures of Olive? I'd love to see what he/she looks like!