If you need to install the plugin, use these instructions.
Once installed, simply navigate to Appearance > Customize > EmPress Color Schemes. There, you will see the One Color Pack plugin palettes ready for your use!
IMPORTANT: If you have the Two Color Pack plugin installed and active, the One Color Pack plugin will appear in the Customizer, but will not work. This is because when both are activated, there are two places your website is trying to pull color codes from, and it’s not sure which should take priority, so it defaults to the Two Color options. If you have bought the Two Color Pack plugin but wish to use the One Color Pack instead, simply head to Plugins > Installed Plugins, look for the Two Color Pack plugin, and deactivate it. Be sure not to delete it! You can always reactivate the plugin if you decide you want a two-color scheme down the road.