It is so simple, that the whole documentation fits in the README. All you need to do is to tell it the table and column names of your existing database and of you go. If you have something more complicated you can also put arbitrary SQL statements in there.

So my configuration is this (I only redacted the company name, the remaining is copied verbatim):

    users.host               = /run/mysqld/mysqld.sock
    users.database           = Company
    users.db_user            = mail
    users.db_passwd          = $(secret-tool lookup user mail@mysql)
    users.table              = User
    users.user_column        = username
    users.password_column    = password
    users.password_crypt     = Y

> and it is not no-code at all

Then tell me how I put your "no-code tool" into the VCS?

> no college degree required

Yeah, which nearly everyone has, but now you need to run through tons of certification programs instead. Which cost a lot of money, so you have the "Certified Rockstar Active Directory Consultant Adviser (TM)"

> it looks like an unpaid community project

> built by paid devs with a verifiable software supply chain.

Which is how most FOSS OS work, which have way more of a verifiable supply chain than your proprietary closed-source OS from Microsoft.

> it is not no-code at all. no college degree required.

Which totally matters, because you want random Joe who hasn't even finished college to be able to mess around with the company authentication setup.