These boys may not reform, but you can try. Look at
@Beekissed 's article about managing difficult cockerels, and
@Shadrach has information too.
With first time chickens, it's likely that you didn't recognize warning behaviors, until actual attacks happened, and you don't have adult roosters and hens to help raise these cockerels either.
Your best bet is to rehome these cockerels, with full disclosure, or send them to freezer camp, and get some chicks next spring, when your then adult hens can help.
You will get lots of conflicting advice here, and some may help, and some not.
At least wear jeans and shoes, and carry a stick to encourage him to stay out of your personal space. Move him away every day, by walking out there confidently, through him, never around. Be ready for sneak attacks from the rear too!
If you have small children or visitors, get him gone ASAP.
Mary