The assemblies folder contains a list of the installed drivers necessary to connect to other data sources. TARGIT supplies a range of Data Drivers (installed separately) for use with TARGIT InMemory Database.
If you don't see the driver/assembly required to connect to your data source system, you will need to connect to this 3rd party driver as a local assembly. Examples of other 3rd party drivers would be the Oracle ADO.NET driver or other similar ADO.NET drivers. In that case, when setting up the Data Source, select the 'Local' assembly location and select the path to the required dll.