Using Page Password plugin is simple and straightforward.
After installing it, a new section becomes available in the administration panel called "Page password".
There it is possible to list all pages with a password set, remove the protection or protect new pages.
Each page can have multiple passwords set: just add the same page twice or more.
It is possible to protect a whole section (page and subpages) by choosing the main page and selecting the recursive checkbox.
If a user tries to access a protected page (or a child of a protected page if recursive option is enabled) it will be asked for a password. If the user already inserted a valid password for this page the password request is skipped, until browser cookies expires or are deleted.
While there are no bug reports, in case anything goes wrong it is possible to remove the protection by editing the file
../packages/page_password/src/Models/PagePasswordModel.php
and replacing line
//return; //Uncomment (remove initial "//") this line if you have been locked out from your site
with
return; //Uncomment (remove initial "//") this line if you have been locked out from your site