There are two run controls in the Fitting module toolbar:
Run. This starts the fitting exercise, using the initial guesses.
Stop. This stops the fitting run. If stop is pressed, no statistics will be calculated as a good fit has not been found. Pressing run after stop continues the fitting run from the current values.
You can move between Data and Parameters and Fitting results screens using the tabs at the top of the screen, changing the setup if necessary as you interpret the results of the fit.