Depends on if the bracelet is held together using pins or screws.
If it's screws, you obviously just need a little screw driver.
If it's pins, you need some kind of pin press. Search amazon for "watch pin remover".
They're pretty cheap.
You might want to pick up a spring bar tool while your at it. You can use that to remove the
bracelet if you want to switch to a strap.
If it's pins, they're usually directional. Look for a little arrow on the bracelet and push the pins
out in that direction. Take note of the pin once it comes out and make sure you put it back
in the same orientation and in the same direction. Be patient and make sure everything lines
up when youre pushing the pins through.
If it's screws, they might be difficult to loosen since they often use some locktite.
Less expensive watches are usually pins though.