Click on the RED DOWNLOAD icon to download a whole set of symbols. Each set of symbols are contained within a ZIP file so you will need to extract the files before you can use them.
The default location of the EFD Symbol Library is - C:\ProgramData\Event Floorplan Designer V5\Symbol Libraries
If you want to change the location of the Symbol Library, you can do that in System Settings.
There are 2 ways to insert Symbols into your drawing: