Show Workspace by selecting menu: View->Workspace or click Workspace tab in the project explorer.

Expand Configuration node in project window by clicking on it, then expand target settings by clicking on target CPU name, LPC2000 is shown below. Expand sub-options by clicking on them.

Edit options by right clicking on the option node and selecting Edit from the pop-up menu. Edit XTAL value to match your board. Edit UART0, verify that Flags are 81DOD and Baud rate is 38400.

Editable option nodes are in Bold text.