Hi bbastias,
If a VBO is not available in the dropdown of the Action stage then at first check if it is available in the Blue Prism folder. You can do this by going to the main screen of BP, then on the File menu click Import. You will automatically be taken to browse to the folder where the VBOs exist.
If it is there, then select the xml file and continue with simple wizard and the VBO will be available in the dropdown after the Import.
VBOs which are not available in the Blue Prism folder will be available for download from the Blue Prism portal under the Products | VBO menu.