Many of Fredo's extensions now require licenses, as do some other authors' work.
These perpetual licenses are relatively inexpensive [typically $7 to $15 each].
There might also be discounted 'bundle' licenses available, e.g. Fredo's bundle contains 8 of his most popular ones.
https://sketchucation.com/purchase.php?plugin=Fredo6Bundle2022
and costs $40/$24 for premium members.
Premium members get considerable % discounts.
You also need to install his help LibeFredo6 [free]
licensed extensions also require the SketchUcation Tools [free] installing which sets up the licensing side of things.
This page covers all current licensed SCF extensions...
https://sketchucation.com/plugin-list.php
This is the general licensing guide...
https://downloads.sketchucation.com/licensing/SCFLicense-Instructions_to_Users.pdf
And this page lets you manage your own licenses...
https://sketchucation.com/webshop/my-licences.php