By default, BBC Symphony Orchestra Discover comes with four techniques for Strings: Long, Spiccato, Pizzicato, and Tremolo. In order to access the Legato translation (essentially a monophonic version of the Long technique), you need to use the Core or Pro templates. These can be found on The Page.
Click on the "Legato" technique track, and you should now be able to play the translated version- indicated by a beaker showing in the middle of the plugin, and a tilde (~) next to the technique name.
