How do I find the source of leakage and temps greater than 200F?

My Breville Dual Boiler BES900XL is about 2.5 years old. I haven’t been using it the last six months due to issues with leakage and temperature. The LCD screen shows temps greater than 200F, even though it is set to 200. More troublesome though, is that the machine leaks from the bottom. I have to refill the tank constantly due to the leakage. I am hoping it is something I can repair myself but I don’t know where to start.

Thankyou!

Christine