If you didn't use turbo tax last year where do you get the 5 digit pin from to complete your tax return

Each year you enter a 5 digit PIN as a "signature" to efile your return.  You can enter any 5 digits.  If you remember the 5 digit PIN you enter this year, you can use it in 2023 instead of your 2021 AGI.

I tried putting in a dummy PIN and it was rejected again..