When you purchase a Panda product, you must activate it using an activation code. If you purchased the product online, you will have received an email message with all the information you need to activate it.
If you have a trial or pre-installed version, you will not need an activation code, because these versions activate automatically.
After you have activated the protection, it updates itself against the new malware threats that appear every day.
Refer to the How to activate your antivirus section.