How can u fix my 35030?

Are you sure it's a dishwasher?
Siemens make clothes washing machine with this number.

As for why no hot water?
Well the machine is capable of heating cold water on its own
Some machines do have a hot water inlet - perhaps your hot water is turned off - perhaps the hot water inlet solenoid valve is defective.

Inlet valves are easy to replace - you find them attached to the hot water hose - and quite inexpensive.

You might consider a repair specialist if you lack the confidence to do it yourself.

Good Luck...
May 2016