Watchpoints are indicated by an eye glas icon in front of the line.
To set a breakpoint on a specific source line, it is easiest to do this in the source code window. If you don't know the exact file and line number of a function, you can set the breakpoint by typing the function name in the edit box above the list and click Add Breakpoint.
You can disable and enable breakpoints by selecting them in the list and clicking Disable or Enable. Or you simply click on the breakpoint in the list using the middle mouse button - just like you enable and disable breakpoints in the source window.
You can set a condition on a breakpoint (so that the program is only stopped if the condition is true) or set an ignore count (so that the program is not stopped the next n times that the breakpoint is hit). To do that, press the Conditional button and enter the condition and/or ignore count.
To set a watchpoint, type an expression in the edit box above the list, then click Add Watchpoint. The program will stop when the value of the expression changes. Note that watchpoints that involve local variables can only be set when the program is stopped in a breakpoint (or has been interrupted by Execution|Break).
To remove the watchpoint, select it from the list and click Remove. If the expression involves a local variable, the watchpoint will be removed automatically when the program leaves the current frame.
You can set a condition and an ignore count on the watchpoint just like on breakpoints by selecting it and clicking Conditional.