A sound of thunder

From this story i understood that Eckel is hunter who went out to the safari , but not just any safari but the one of the pass where no man was alive yet to hunt a dinosaurs.He get strict rulers where he can't step out of the pass and he was only allowed to shoot when he was told to.If he didn't follow the rules he would be charged an extra 10,000 and also he would mess up the future.