Click on the hamburger menu (three horizontal lines) in the top right corner of the Brushes panel. Select or look for the cloud icon.
If you have an older version of Photoshop (CS6 or earlier) that does not support Creative Cloud Libraries, and you have legitimately purchased the legacy packs, here is how to install them: Kyle T Webster Brushes Pack Free Download
This is the only scenario where a "free download" might seem tempting. If you do not pay for Photoshop, you cannot legally get the Kyle T. Webster brushes. Click on the hamburger menu (three horizontal lines)