I have a rocket and whenever i launch it the parachute automatically deploys and i cant stop it from doing that. Help please?
You're having trouble with staging, not action groups.
Along the right side of the screen during rocket construction, or the left side during flight, are your stages. Each orange bar is the container for one stage. When you press the staging button, everything in the next stage activates. You have your engines and your parachutes in the same stage, so it's doing what you're telling it to: activate them both at the same time.
If you hover over the staging, you'll notice [+] and [-] icons appear. Press the plus icon to add a new, empty stage. Move your parachutes to this new stage. Then make sure the parachute stage is above your engines stage, if necessary, by clicking on the orange bar and dragging the whole parachute stage to the stop of the stack.
Staging is a key construction tool and as important as how you put the rocket pieces together. Once you know how to use stages, you'll find that getting staging just right is as much a part of the fun of the game as building the rocket itself.