This is an Adobe Photoshop CC 2019 tutorial showing you how to install patterns by downloading the PAT file, loading the patterns and applying them. Here are more Photoshop install tutorials for actions, brushes and fonts.
1. Download PAT File
Download the Photoshop patterns PAT file.
2. Load Patterns
Open Photoshop, in Layers panel, double-click your layer > check Pattern Overlay.
Click the drop-down arrow on Pattern: > click the gear icon.
Load Patterns… > select PAT file > click Open.
To make your patterns show up on the list, place PAT file in Finder > Applications > Adobe Photoshop CC 2019 > Presets > Patterns.
3. Apply Pattern
Select your pattern (You can play with Blend Mode, Opacity and Scale.) > click OK.