A Honda Civic's battery may often be replaced in a few straightforward steps. Here is a general description of what happens:
Make sure the key is out of the ignition and turn the engine off. Find the battery, which is often on the driver's side of the engine compartment.
Then, disconnect the negative cable (black) from the battery terminal by loosening the clamp with a wrench or pair of pliers.
Next, disconnect the positive cable (red) from the battery terminal by loosening the clamp once more with a wrench or pair of pliers.
If the battery is being held in place by any brackets or other holding mechanisms, remove them.
Remove the old battery from the car with care, then set it aside. Make sure the replacement battery is securely fastened and positioned before installing it.
Reconnect the negative cable (blue) first, then the positive cable (red) to the positive battery terminal (black). To check that the new battery is operating properly, start the engine.