Those styles grow out fast so you should consider a temporary dye perhaps even just a hair spray with dye in it. That way you don't have to bleach and you can color the top to match your clothes or shoes etc.

If you still want to do it then save the hair from the hair cut. Dye the cut hair to experiment with the type, color, and developer for a tint that matches the results you want.

You can probably just use 40 developer in your hair for about 45 minutes. Always do a deep conditioning treatment after doing any process.