Hello @jmcharg and welcome to the forum!
You can download the brushes from the links in the first posting of this topic:
There you find these two links (they will work too, but you don’t get the additional information from the topic):
In that first post, and in the whole topic you will find more information about those bundles, the brushes they contain and more.
A bundle is installed in Krita via the menu ‘‘Settings’’ >> ‘‘Manage Resource Libraries…’’ and in the opening dialog you have to click the button + Import in the next dialog browse to the downloaded bundle, select it and confirm the selection. Now Krita imports that bundle, and you can use its content, so the brushes in case of this bundle.
In case this BUNDLE comes in an archive-file, like ZIP or RAR for instance, then you have to unpack the archive to get the BUNDLE-File it contains, then you can proceed as described above.
Michelist