Polycom vvx 300 admin password reset

How do I enter letters; A, D, F.
What the heck does
A->a1
a->1A
1->Aa
mean?

Found it!
https://emak.tech/support/polycom-factory-reset-without-password/

You must switch between A-> and 1->.
When entering the letter F, select A->a1, the press 333.

73, Chuck