Terrarium setup and heating

[dmallia]

I have a 45cmx45cmx45cm exo terra terrarium and a 28cmx28cm 14 Watt heating mat. Soon I will be getting my first green tree frog. I surfed the internet and found some information especially about the heating. Some say to put the heating mat at the bottom of the terrarium and than place a rock on where the heating mat is attached, so it will absorb the heat and than the frog can go on the rock for heat. Some say to put the heating mat at one side of the terrarium so when they will be on the branches since they are tree frogs there will be heat. Where should I place my heat mat?

Now this is my current setup.



What do you think? I know that I need to add more accessories (plants, branches, etc.) but don't know what and where to add them. Any suggestions?