NodeRED provides over 3200 libraries with different Nodes to create connectivity to a lot of different systems and devices.
To install one of them just open the palette manager form the submenu in the the upper right corner. In the pallet manager window click on the install tab and search for the library you like to install. By clicking on the install button the libraries will be installed in NodeRED and provided in the Nodes palette on the left side of the screen. Depending on the power of the host machine, this can take a while.