Choose Third-Party Liability + Limited Cover to get more than the basic third-party cover. This will not only cover you when you cause damage to other people’s property with your car, but will also cover other kinds of damage, such as window damage, break-in damage, and damage caused by a collision with an animal. If you prefer to also be covered when you cause damage to your car yourself, go for Third-Party Liability + Comprehensive Cover (All-risks cover).
Submitted everything? Then take out the car insurance. You choose when the insurance takes effect: immediately or later.