When you enter your Passcode incorrectly, after a few attempts you will have to wait for the next attempt. The waiting time will be extended each time you enter the code incorrectly. If you have forgotten your Passcode, it cannot be restored.
Unfortunately, this means that your iPhone must be restored to the factory settings if you do NOT remember the code.
You can see how to do a Factory Restore without a computer here:
If you see an iPhone or iPad unavailable message or Security Lockout screen - Apple Support
If you want to do a Factory Restore from a computer, see here:
If you forgot your iPhone passcode - Apple Support