How can I unlock my Mac mini if I forgot the password?

I'm not sure what you mean by the "Locator". If you mean that your Mac is Activation Locked through Find My, you will need to recover your Apple Account so you can get in and turn off Activation Lock for that Mac. See:

If you forgot your Apple Account password - Apple Support

If that is not what you mean, please clarify.

Regards.

Yes, you will need to create a new, different password. This time write the information down for the next time you need it.