To do so, navigate to Tools > Manage wine versions.
The application will download whatever version you'll say in ~/.playonlinux/WineVersions/
Apart from the repository which you can see on clicking the 'install' button you can run third party *.exe in the same dialog by going to 'install a .pol package or an unsupported application', then you'll be greeted by 2 options, select the manual install one, and do whatever the wizard says.
With POL, you can use the latest WINE and manage all wine prefix without using long commands.
You can even use the wine versions in ~/.playonlinux/WineVersions directly (you can see the wine executable in the usr/bin directory), no harm in that. Create an alias for ease.