Once the tabs have been properly located, insert one tool on each side to loosen compress the base and apply downward pressure on the outer handle. For this the top end of the handle needs to rest against a solid base. It does require a considerable amount of downward force to accomplish this.
With the tabs loosened and the handle opushed downward, the inner workings of the toothbrush will loosen and pop out of the handle.
Remove the mechanics out of the handle.